* 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
