Consolidate GHA pipeline (cross-platform tests, PyPI releases)

[bittner]

The current GHA workflows for tests are split up between "Linux + macOS" and "Windows", and there is no workflow for releasing to PyPI.

Would you be interested in a PR to consolidate the unit test execution for all architectures (example) and add a release workflow that reacts on Git tags (example)?

Implementation note: In order to make the test execution cross-platform it's possible to move the prerequisite installation to a script and call the script(s) from the YAML configuration. (Explanation/StackOverflow)

This might also address/fix issue #146 as a side-effect.

[LudovicRousseau]

I do not need (and don't want) to automate PyPI publishing.

[bittner]

Maybe there is a misunderstanding: Automating intends that you control when to release, but you don't have to do what needs to be done for that.

The process implemented by the example linked above is based on pushing a Git (version) tag. The credentials you can add in the GitHub project settings. You have the control.