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
`pypyX.Y.exe` executables are missing from PyPy archives on Windows before v7.3.9 (X.Y < 3.9)
`pypy2.7` symlinks are also missing from macOS/Linux PyPy archives before v7.3.9
relates to #346
* test for pypy new version notation
* formatting
* uncommented condition
* test
* added pypy to test matrix
* test
* test
* restored all tests
* removed logs, added multiarch support for toolcache
* reduced test matrix
* removed extra condition about arch
