----------------
- Add Python 3.8-3.10 to tox.ini. Remove old Python versions.
[stefan]
- Replace deprecated ``python setup.py test`` in tox.ini.
[stefan]
- Remove deprecated ``test_suite`` and ``tests_require`` from setup.py.
[stefan]
- Move metadata to setup.cfg and add a pyproject.toml file.
[stefan]
- Include tests in sdist but not in wheel.
[stefan]