Updating contribution guidelines
Per the discussion at #4032, here are some updates to the contributions guidelines. This is to start the discussion among the maintainers.

I just went through the review process, and some of the changes here are to clarify some things I encountered going through the process.

I made some changes  that I think should be added related to modern Go, like:
- A project should have at least one official release so it can be tracked in go.mod
- A project should maintain compatibility with Go, if not the most recent version, at least a version before that.

I also gave specific directions on how to add an item, and how to remove.

The goal of all of this is to give clear directions for people who want to help maintain the project, and to ulitimately keep its quality high.

.github/PULL_REQUEST_TEMPLATE.md
> Please check if what you want to add to `awesome-go` list meets [quality standards](https://github.com/avelino/awesome-go/blob/main/CONTRIBUTING.md#quality-standards) before sending pull request. Thanks!

**Please provide package links to:**

- repo link (github.com, gitlab.com, etc):
- pkg.go.dev:
- goreportcard.com:
- coverage service link ([codecov](https://codecov.io/), [coveralls](https://coveralls.io/), [gocover](http://gocover.io/) etc.):

**Note**: _that new categories can be added only when there are 3 packages or more._

**Make sure that you've checked the boxes below before you submit PR:**
_not every repository (project) will fit into every option, but most projects should_

- [ ] I have added my package in alphabetical order.
- [ ] I have an appropriate description with correct grammar.
- [ ] I know that this package was not listed before.
- [ ] I have added pkg.go.dev link to the repo and to my pull request.
- [ ] I have added coverage service link to the repo and to my pull request.
- [ ] I have added goreportcard link to the repo and to my pull request.
- [ ] I have read [Contribution guidelines](https://github.com/avelino/awesome-go/blob/main/CONTRIBUTING.md#contribution-guidelines), [maintainers note](https://github.com/avelino/awesome-go/blob/main/CONTRIBUTING.md#maintainers) and [Quality standard](https://github.com/avelino/awesome-go/blob/main/CONTRIBUTING.md#quality-standards).

Thanks for your PR, you're awesome! :+1:

> Please check if what you want to add to `awesome-go` list meets [quality standards](https://github.com/avelino/awesome-go/blob/main/CONTRIBUTING.md#quality-standards) before sending pull request. Thanks!

**Please provide package links to:**

- repo link (github.com, gitlab.com, etc):
- pkg.go.dev:
- goreportcard.com:
- coverage service link ([codecov](https://codecov.io/), [coveralls](https://coveralls.io/), [gocover](http://gocover.io/) etc.):

**Note**: _that new categories can be added only when there are 3 packages or more._

**Make sure that you've checked the boxes below that apply before you submit PR.**
_Not every repository (project) will require every option, but most projects should. Check the Contribution Guidelines for detials._

- [ ] The package has been added to the list in alphabetical order.
- [ ] The package has an appropriate description with correct grammar.
- [ ] As far as I know, the package has not been listed here before.
- [ ] The repo documentation has a pkg.go.dev link.
- [ ] The repo documentation has a coverage service link.
- [ ] The repo documenation has a goreportcard link.
- [ ] The repo has a version-numbered release and a go.mod file.
- [ ] I have read the [Contribution Guidelines](https://github.com/avelino/awesome-go/blob/main/CONTRIBUTING.md#contribution-guidelines), [Maintainers Note](https://github.com/avelino/awesome-go/blob/main/CONTRIBUTING.md#maintainers) and [Quality Standards](https://github.com/avelino/awesome-go/blob/main/CONTRIBUTING.md#quality-standards).
- [ ] The repo has a continuous integration process that automatically runs tests that must pass before new pull requests are merged.
- [ ] The authors of the project do not commit directly to the repo, but rather use pull-requests that run the continuous-integration process.

Thanks for your PR, you're awesome! :+1:

@phanirithvij I think it's important for the contributor to read, I know we have it in the contribution document (which you thought should be updated), but I think it's important to bring it into the pull request template - even though I know few people read it