Support Django 5.2
As a pre-requisite for #1093 and to help support the upload of Django 5.2 to Debian unstable/forky, we should make sure that we fully support Django 5.2. From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1102743#66 it seems like that at least an integration test is failing with Django 5.2:
https://debusine.debian.net/debian/developers/artifact/3674847/file/integration-tests-workflow-debian-pipeline-stdout
https://debusine.debian.net/debian/developers/work-request/631924/
But that test is not recent, so it might be worth rerunning it first.
issue