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).
This versioning scheme is consistent with other
tools in the python ecosystem so it feels more natural
and allows better interaction with other tools.
fixes#346
