Update base image?

[rpgoldman]

The SWI Prolog Docker images are built on Debian Bookworm, which is supposed to EOL this June. Would it be possible to transition from Bookworm ("oldstable") to Trixie ("stable") sometime soon? This might be as easy as changing one line in update.sh either to build only with trixie, or to add trixie to bookworm.

I could have a shot at this and giving a MR, if you would prefer.

[JanWielemaker]

I'll put it on the agenda. I've got all the testing in place, so there is no need for a PR.