Added
- Added Python 3.11 support.
- Added Django 4.1 support.
Changed
- Remove upper boundary on supported Python version.
- Python 3.10 tests now only run against Django 3.2+, because Django <3.2 does
not support Python 3.10.
- Specify a minimum `attrs` version of `21.4.0`.
Fixed
- Fix broken CI by removing `tox-poetry-dev-dependencies`.