Compatibility testing with Tox

If tox is set to "y" project uses Tox to test compatibility with multiple Python versions. By default, the project is tested with Python 3.10 and 3.11. Testing is done automatically in the CI/CD pipeline on every pull request, merge to main, and on each release.

If you want to add more Python versions you can simply add them to tox.ini and to the separate workflows in .github.