Add typechecking

Add analysis:typecheck job to .gitlab-ci.yml using mypy

How does Ruff compare to Mypy, or Pyright, or Pyre?

Ruff is a linter, not a type checker. It can detect some of the same problems that a type checker can, but a type checker will catch certain errors that Ruff would miss. The opposite is also true: Ruff will catch certain errors that a type checker would typically ignore.

For example, unlike a type checker, Ruff will notify you if an import is unused, by looking for references to that import in the source code; on the other hand, a type checker could flag that you passed an integer argument to a function that expects a string, which Ruff would miss. The tools are complementary.

It's recommended that you use Ruff in conjunction with a type checker, like Mypy, Pyright, or Pyre, with Ruff providing faster feedback on lint violations and the type checker providing more detailed feedback on type errors.