0.21.0

• remove noqa: F401 from __init__.py files
• add type checking to documentation conf.py
• enforces lf line ending with ruff
• target python version 3.9 instead of 3.10 for lint
• remove setup.py mentions from pyproject.toml
• remove pytest utility requires_module
• add explicit codecov token to support codecov/codecov-action@v4
• pin pytest to 8.0 or above due to backward incompatible change on pytest.warns
• run twine check before upload to PyPI

Full Changelog: 0.20.0...0.21.0