chore(ci): Update to add Django 5.0 (alpha) support.

[sarahboyce]

Submitting Pull Requests

Hello 👋 thank you for maintaining this package!!!
We wanted to help set up testing against Django 5.0. It's still a little early (won't be released until December) but this hopefully gives the basic structure and we can update it when wanted.

General

• Make sure you use semantic commit messages.
  Examples: "fix(google): Fixed foobar bug", "feat(accounts): Added foobar feature".
• All Python code must formatted using Black, and clean from pep8 and isort issues.
• JavaScript code should adhere to StandardJS.
• If your changes are significant, please update ChangeLog.rst.
• If your change is substantial, feel free to add yourself to AUTHORS.

[coveralls]

coverage: 91.737%. remained the same when pulling 16d1352 on sarahboyce:django-5-0-testing into 4f24552 on pennersr:main.