Run core tests in Safari. Partially addresses https://github.com/pyodide/pyodide/issues/989

It runs, but there are several test failures, I'll open separate issues about those.
# .readthedocs.yml
# Read the Docs configuration file
# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details

# Required
version: 2

sphinx:
  configuration: docs/conf.py

formats: all

python:
  install:
    - requirements: docs/requirements-doc.txt

build:
  os: ubuntu-20.04
  tools:
    python: "3.10"
    nodejs: "14"

# .readthedocs.yml
# Read the Docs configuration file
# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details

# Required
version: 2

sphinx:
  configuration: docs/conf.py

formats: all

python:
  install:
    - requirements: docs/requirements-doc.txt

build:
  os: ubuntu-20.04
  tools:
    python: "3.10"
    nodejs: "14"
