Treat some warnings as errors in CI

[tim-schilling]

Description

Explicitly ignores the RedirectPanel's deprecation warning.

Checklist:

• [x] I have added the relevant tests for this change.
• [x] I have added an item to the Pending section of docs/changes.rst.

[github-actions[bot]]

Coverage report

This PR does not seem to contain any modification to coverable code.

[tim-schilling]

I forgot to update the changelog after I switched away from error. I'm going to change this though to follow what Adam does with django-mysql then ignore our specific warning.

      -W error::ResourceWarning \
      -W error::DeprecationWarning \
      -W error::PendingDeprecationWarning \