Suggest updating to a more recent base.

[wom-bat]

The Dockerfiles are currently based on Debian Bullseye, which is the old stable release.

I'd suggest providing an alternate branch for trixie (the release that is due this year) to be ready for it when it comes.
Then we can (finally) get rid of python 2.

[lsf37]

Trixie is still "testing", but we should probably update to the current stable now (bookworm).