This allows to specify version like `3.11` or `pypy3.10` in workflows before those versions are released.
This lessen the burden for users of `setup-python` by not having to modify their workflow twice: once when a pre-release is available (e.g. `3.11-dev`) and once when the first stable release is published (e.g. `3.11`)
This option allows to specify if the action shall update environment variables (default) or not.
This allows to use the setup-python action in a composite action without side effect (except downloading/installing python if version is missing).
* add support for python-version-file
* Update action.yml
* update to v4, remove python-version default
* python-version overrides python-version-file, like setup-node
* checks '.python-version' by default if nothing else specified
* update tests, update to checkout@v3
* update build
* appease the linter
* remove old test for default python version
* revert readme changes
* update build
