chore: modernize ruff config to work with ruff >= v0.2

[afuetterer]

Hi, this is my first PR to the project. Please let me know, if I missed anything.

This PR modernizes the ruff configuration to work with ruff >= v0.2.

It gets rid of these warnings:

$ ruff ninja tests
warning: `ruff <path>` is deprecated. Use `ruff check <path>` instead.
warning: The top-level linter settings are deprecated in favour of their counterparts in the `lint` section. Please update the following options in `pyproject.toml`:
  - 'ignore' -> 'lint.ignore'
  - 'select' -> 'lint.select'
  - 'per-file-ignores' -> 'lint.per-file-ignores'
All checks passed!