Stop building nightly image? #217

I have fixed the nightly image, because I was annoyed by the mails of failing jobs that I got each night. But we could also stop building it altogether. @davisagli thought "we already decided to stop releasing the nightly image. As far as I know no one is using it."

There is some value in having a nightly image.
But for me it is fine to stop building the nightly image.

What do others think?

Practically I would then want to remove all related files, and edit anything that mentions the nightly, like the Makefile:

.github/workflows/nightly.yml
Dockerfile.nightly
helpers/pip-from-buildout-coredev.py

For good measure we should remove those files from all branches. Maybe for branches older than 6.2.x only remove the workflow file.

Alternatives to a nightly could be:

• A -dev variant which takes its versions from https://dist.plone.org/release/6.2-dev/. When I update this directory, I could manually trigger a new job for building, testing, and pushing the image.
• A -sec variant which would use a not yet existing dist.plone.org directory 6.2-sec. This would then be the previous 6.2 version plus security fixes. Triggered manually. Could also be done weekly, which should give us the latest python:3.13-slim-bookworm base image, including all security fixes this has on Python and OS level.

But @fredvd already has ideas for how to build/specify variants, so let's not add new ones until that has been crystallised.