Support Django 5.2

As it's the newest LTS version, we should probably aim to support it in the next DSC release for any new apps starting out now.

Django 5.2 officially supports the following Django versions: 3.10, 3.11, 3.12, 3.13

Supporting this version will mean turning on deprecation warnings, and testing with the above Python and Django versions.

Supporting *all* of these Python versions is not a goal of the next release, but we might as well see which ones come free.

No file or test is named in the issue. Start by locating the package dependency configuration and test setup, then enable deprecation warnings and test Django 5.2 against the stated Python and Django versions. Done means the supported combinations are verified and any Python versions that cannot be supported are explicitly identified for the next release.

Written by the indexing model from the issue text.