ruff format, support numpy 2, remove Python 3.8

[hagenw]

As ruff now supports formatting of code like black, we extend pre-commit to also format the code using ruff.

We also add support for numpy 2.0 and remove support for Python 3.8.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.0%. Comparing base (33be05c) to head (a0fb1bd).

Additional details and impacted files

Files	Coverage Δ
audmath/__init__.py	100.0% <ø> (ø)
audmath/core/api.py	100.0% <100.0%> (ø)
audmath/core/conftest.py	100.0% <100.0%> (ø)
audmath/core/utils.py	100.0% <ø> (ø)