add type checker to pre-commit/CI

[elmjag]

It would nice to include a type checking tools to our pre-commit/CI checks.

@marcus-oscarsson suggest using pyright: https://github.com/microsoft/pyright

Another option is of cause the classical mypy: https://mypy-lang.org/

[fabcor-maxiv]

I have used mypy only, never pyright or any other type checking tool. So I believe that I can be reasonably helpful with mypy, but I am perfectly fine with using something else.

And yes, I am for the introduction of some type checker tool.