Finsberg/change testing workflow

[finsberg]

• Setup matrix for testing python versions.
• Add configurations for pytest to pyproject.toml
• Move setup.cfg to .flake8 since it only contains flake8 configurations.
• Skip testing of building docs - this is done in the build docs workflow anyway
• Run coverage report after test suit - no need to run pytest one extra time

[finsberg]

One thing I am thinking is if we need to run this workflow on pull-requests to main when we already run it on every push?

[jorgensd]

One thing I am thinking is if we need to run this workflow on pull-requests to main when we already run it on every push?

No, we do not. I would suggest doing it on PRs

[finsberg]

One thing I am thinking is if we need to run this workflow on pull-requests to main when we already run it on every push?

No, we do not. I would suggest doing it on PRs

Run test CI only when push or PR to main: b0a76c4