1. Allow build, lint, test & bash with the celery container using `make` commands.
2. Added CI to build the docker image to make sure it doesn't get broken in a future PR without knowing.
3. Default to Python 3.11 in the Dockerfile if not set otherwise via .python-version (pyenv).

For example running `make docker-lint` from the `celery` repo root:
```bash
make docker-lint

[+] Creating 4/0
 ✔ Container docker-azurite-1   Running                                                                                                                                           0.0s
 ✔ Container docker-rabbit-1    Running                                                                                                                                           0.0s
 ✔ Container docker-dynamodb-1  Running                                                                                                                                           0.0s
 ✔ Container docker-redis-1     Running                                                                                                                                           0.0s
ROOT: will run in automatically provisioned tox, host /home/developer/.pyenv/versions/3.11.5/bin/python3.11 is missing [requires (has)]: tox-gh-actions
ROOT: recreate env because python changed version_info=[3, 9, 13, 'final', 0]->[3, 11, 5, 'final', 0] | executable='/Users/nusnus/.pyenv/versions/3.9.13/bin/python3.9'->'/home/developer/.pyenv/versions/3.11.5/bin/python3.11' | virtualenv version='20.24.4'->'20.24.5'
ROOT: remove tox env folder /home/developer/celery/.tox/.tox
ROOT: install_deps> python -I -m pip install tox tox-gh-actions
ROOT: provision> .tox/.tox/bin/python -m tox -e lint
ROOT: tox-gh-actions won't override envlist because tox is not running in GitHub Actions
.pkg: _optional_hooks> python /home/developer/celery/.tox/.tox/lib/python3.11/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__
.pkg: get_requires_for_build_editable> python /home/developer/celery/.tox/.tox/lib/python3.11/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__
.pkg: build_editable> python /home/developer/celery/.tox/.tox/lib/python3.11/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__
lint: install_package> python -I -m pip install --force-reinstall --no-deps /home/developer/celery/.tox/.tmp/package/17/celery-5.3.4-0.editable-py3-none-any.whl
lint: commands[0]> pre-commit run --all-files --show-diff-on-failure
[INFO] Initializing environment for https://github.com/asottile/pyupgrade.
[INFO] Initializing environment for https://github.com/PyCQA/flake8.
[INFO] Initializing environment for https://github.com/asottile/yesqa.
[INFO] Initializing environment for https://github.com/pre-commit/pre-commit-hooks.
[INFO] Initializing environment for https://github.com/pycqa/isort.
[INFO] Initializing environment for https://github.com/pre-commit/mirrors-mypy.
[INFO] Installing environment for https://github.com/asottile/pyupgrade.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/PyCQA/flake8.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/asottile/yesqa.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/pre-commit/pre-commit-hooks.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/pycqa/isort.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/pre-commit/mirrors-mypy.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
pyupgrade................................................................Passed
flake8...................................................................Passed
Strip unnecessary `# noqa`s..............................................Passed
check for merge conflicts................................................Passed
check toml...............................................................Passed
check yaml...............................................................Passed
mixed line ending........................................................Passed
isort....................................................................Passed
mypy.....................................................................Passed
.pkg: _exit> python /home/developer/celery/.tox/.tox/lib/python3.11/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__
  lint: OK (35.25=setup[3.34]+cmd[31.92] seconds)
  congratulations :) (37.49 seconds)
```


The `make help` is also modified:
```bash
make help
docs                 - Build documentation.
test-all             - Run tests for all supported python versions.
distcheck ---------- - Check distribution for problems.
  test               - Run unittests using current python.
  lint ------------  - Check codebase for problems.
    apicheck         - Check API reference coverage.
    configcheck      - Check configuration reference coverage.
    readmecheck      - Check README.rst encoding.
    contribcheck     - Check CONTRIBUTING.rst encoding
    flakes --------  - Check code for syntax and style errors.
      flakecheck     - Run flake8 on the source code.
      flakepluscheck - Run flakeplus on the source code.
readme               - Regenerate README.rst file.
contrib              - Regenerate CONTRIBUTING.rst file
clean-dist --------- - Clean all distribution build artifacts.
  clean-git-force    - Remove all uncommitted files.
  clean ------------ - Non-destructive clean
    clean-pyc        - Remove .pyc/__pycache__ files
    clean-docs       - Remove documentation build artifacts.
    clean-build      - Remove setup artifacts.
bump                 - Bump patch version number.
bump-minor           - Bump minor version number.
bump-major           - Bump major version number.
release              - Make PyPI release.

Docker-specific commands:
  docker-build			- Build celery docker container.
  docker-lint        		- Run tox -e lint on docker container.
  docker-unit-tests		- Run unit tests on docker container, use '-- -k <TEST NAME>' for specific test run.
  docker-bash        		- Get a bash shell inside the container.
```
Celery Docker Upgrades. 1. Allow build, lint, test & bash with the celery container using `make` commands.
2. Added CI to build the docker image to make sure it doesn't get broken in a future PR without knowing.
3. Default to Python 3.11 in the Dockerfile if not set otherwise via .python-version (pyenv).

For example running `make docker-lint` from the `celery` repo root:
```bash
make docker-lint

[+] Creating 4/0
 ✔ Container docker-azurite-1   Running                                                                                                                                           0.0s
 ✔ Container docker-rabbit-1    Running                                                                                                                                           0.0s
 ✔ Container docker-dynamodb-1  Running                                                                                                                                           0.0s
 ✔ Container docker-redis-1     Running                                                                                                                                           0.0s
ROOT: will run in automatically provisioned tox, host /home/developer/.pyenv/versions/3.11.5/bin/python3.11 is missing [requires (has)]: tox-gh-actions
ROOT: recreate env because python changed version_info=[3, 9, 13, 'final', 0]->[3, 11, 5, 'final', 0] | executable='/Users/nusnus/.pyenv/versions/3.9.13/bin/python3.9'->'/home/developer/.pyenv/versions/3.11.5/bin/python3.11' | virtualenv version='20.24.4'->'20.24.5'
ROOT: remove tox env folder /home/developer/celery/.tox/.tox
ROOT: install_deps> python -I -m pip install tox tox-gh-actions
ROOT: provision> .tox/.tox/bin/python -m tox -e lint
ROOT: tox-gh-actions won't override envlist because tox is not running in GitHub Actions
.pkg: _optional_hooks> python /home/developer/celery/.tox/.tox/lib/python3.11/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__
.pkg: get_requires_for_build_editable> python /home/developer/celery/.tox/.tox/lib/python3.11/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__
.pkg: build_editable> python /home/developer/celery/.tox/.tox/lib/python3.11/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__
lint: install_package> python -I -m pip install --force-reinstall --no-deps /home/developer/celery/.tox/.tmp/package/17/celery-5.3.4-0.editable-py3-none-any.whl
lint: commands[0]> pre-commit run --all-files --show-diff-on-failure
[INFO] Initializing environment for https://github.com/asottile/pyupgrade.
[INFO] Initializing environment for https://github.com/PyCQA/flake8.
[INFO] Initializing environment for https://github.com/asottile/yesqa.
[INFO] Initializing environment for https://github.com/pre-commit/pre-commit-hooks.
[INFO] Initializing environment for https://github.com/pycqa/isort.
[INFO] Initializing environment for https://github.com/pre-commit/mirrors-mypy.
[INFO] Installing environment for https://github.com/asottile/pyupgrade.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/PyCQA/flake8.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/asottile/yesqa.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/pre-commit/pre-commit-hooks.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/pycqa/isort.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
[INFO] Installing environment for https://github.com/pre-commit/mirrors-mypy.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
pyupgrade................................................................Passed
flake8...................................................................Passed
Strip unnecessary `# noqa`s..............................................Passed
check for merge conflicts................................................Passed
check toml...............................................................Passed
check yaml...............................................................Passed
mixed line ending........................................................Passed
isort....................................................................Passed
mypy.....................................................................Passed
.pkg: _exit> python /home/developer/celery/.tox/.tox/lib/python3.11/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__
  lint: OK (35.25=setup[3.34]+cmd[31.92] seconds)
  congratulations :) (37.49 seconds)
```


The `make help` is also modified:
```bash
make help
docs                 - Build documentation.
test-all             - Run tests for all supported python versions.
distcheck ---------- - Check distribution for problems.
  test               - Run unittests using current python.
  lint ------------  - Check codebase for problems.
    apicheck         - Check API reference coverage.
    configcheck      - Check configuration reference coverage.
    readmecheck      - Check README.rst encoding.
    contribcheck     - Check CONTRIBUTING.rst encoding
    flakes --------  - Check code for syntax and style errors.
      flakecheck     - Run flake8 on the source code.
      flakepluscheck - Run flakeplus on the source code.
readme               - Regenerate README.rst file.
contrib              - Regenerate CONTRIBUTING.rst file
clean-dist --------- - Clean all distribution build artifacts.
  clean-git-force    - Remove all uncommitted files.
  clean ------------ - Non-destructive clean
    clean-pyc        - Remove .pyc/__pycache__ files
    clean-docs       - Remove documentation build artifacts.
    clean-build      - Remove setup artifacts.
bump                 - Bump patch version number.
bump-minor           - Bump minor version number.
bump-major           - Bump major version number.
release              - Make PyPI release.

Docker-specific commands:
  docker-build			- Build celery docker container.
  docker-lint        		- Run tox -e lint on docker container.
  docker-unit-tests		- Run unit tests on docker container, use '-- -k <TEST NAME>' for specific test run.
  docker-bash        		- Get a bash shell inside the container.
```
"""Thread execution pool."""
from __future__ import annotations

from concurrent.futures import Future, ThreadPoolExecutor, wait
from typing import TYPE_CHECKING, Any, Callable

from .base import BasePool, apply_target

__all__ = ('TaskPool',)

if TYPE_CHECKING:
    from typing import TypedDict

    PoolInfo = TypedDict('PoolInfo', {'max-concurrency': int, 'threads': int})

    # `TargetFunction` should be a Protocol that represents fast_trace_task and
    # trace_task_ret.
    TargetFunction = Callable[..., Any]


class ApplyResult:
    def __init__(self, future: Future) -> None:
        self.f = future
        self.get = self.f.result

    def wait(self, timeout: float | None = None) -> None:
        wait([self.f], timeout)


class TaskPool(BasePool):
    """Thread Task Pool."""
    limit: int

    body_can_be_buffer = True
    signal_safe = False

    def __init__(self, *args: Any, **kwargs: Any) -> None:
        super().__init__(*args, **kwargs)
        self.executor = ThreadPoolExecutor(max_workers=self.limit)

    def on_stop(self) -> None:
        self.executor.shutdown()
        super().on_stop()

    def on_apply(
        self,
        target: TargetFunction,
        args: tuple[Any, ...] | None = None,
        kwargs: dict[str, Any] | None = None,
        callback: Callable[..., Any] | None = None,
        accept_callback: Callable[..., Any] | None = None,
        **_: Any
    ) -> ApplyResult:
        f = self.executor.submit(apply_target, target, args, kwargs,
                                 callback, accept_callback)
        return ApplyResult(f)

    def _get_info(self) -> PoolInfo:
        info = super()._get_info()
        info.update({
            'max-concurrency': self.limit,
            'threads': len(self.executor._threads)
        })
        return info

"""Thread execution pool."""
from __future__ import annotations

from concurrent.futures import Future, ThreadPoolExecutor, wait
from typing import TYPE_CHECKING, Any, Callable

from .base import BasePool, apply_target

__all__ = ('TaskPool',)

if TYPE_CHECKING:
    from typing import TypedDict

    PoolInfo = TypedDict('PoolInfo', {'max-concurrency': int, 'threads': int})

    # `TargetFunction` should be a Protocol that represents fast_trace_task and
    # trace_task_ret.
    TargetFunction = Callable[..., Any]


class ApplyResult:
    def __init__(self, future: Future) -> None:
        self.f = future
        self.get = self.f.result

    def wait(self, timeout: float | None = None) -> None:
        wait([self.f], timeout)


class TaskPool(BasePool):
    """Thread Task Pool."""
    limit: int

    body_can_be_buffer = True
    signal_safe = False

    def __init__(self, *args: Any, **kwargs: Any) -> None:
        super().__init__(*args, **kwargs)
        self.executor = ThreadPoolExecutor(max_workers=self.limit)

    def on_stop(self) -> None:
        self.executor.shutdown()
        super().on_stop()

    def on_apply(
        self,
        target: TargetFunction,
        args: tuple[Any, ...] | None = None,
        kwargs: dict[str, Any] | None = None,
        callback: Callable[..., Any] | None = None,
        accept_callback: Callable[..., Any] | None = None,
        **_: Any
    ) -> ApplyResult:
        f = self.executor.submit(apply_target, target, args, kwargs,
                                 callback, accept_callback)
        return ApplyResult(f)

    def _get_info(self) -> PoolInfo:
        info = super()._get_info()
        info.update({
            'max-concurrency': self.limit,
            'threads': len(self.executor._threads)
        })
        return info
