Add linting workflow with yamllint; fix linting issues

[felixfontein]

The indents in the release workflow were different for different parts of the file. This fixes it, and adds a yamllint step for the whole repository.

The automatically generated/updated files are ignored.

[gotmax23]

I would prefer to have a nox or tox or pre-commit configuration (whichever you prefer but perhaps a good idea to standardize on nox) to run yamllint. This would make it easier to add others linters in the future and should make things easier for contributors.

[felixfontein]

In that case I'd prefer nox over both the other tools.

[felixfontein]

There's now a new nox session lint.

[mariolenz]

LGTM but I don't know nox good enough to say if this is really the best solution. So I'll only comment and not approve.

Anyway: Release early, release often! We can improve this later. If @gotmax23 approves, take this as an approval from me also.

@felixfontein I'm no expert on GH workflows but it looks like you've implemented that a new release can't be published on PyPI when the PR isn't merged yet...? If I'm right, I think that's a good idea! You know why 😉

[felixfontein]

@felixfontein I'm no expert on GH workflows but it looks like you've implemented that a new release can't be published on PyPI when the PR isn't merged yet...? If I'm right, I think that's a good idea! You know why 😉

Nope, this PR is unrelated to that ... #390 should prevent accidental releases. I guess we can test it tomorrow with 10.0.0a2, since ansible-core 2.17.0rc1 got released today.

[felixfontein]

If nobody objects, I'm going to merge this soon.