Bump base image to Ubuntu 24.04 LTS

[yuvipanda]

Moves from 22.04 to 24.04

[yuvipanda]

@manics thoughts on rolling this into the release?

[manics]

Sounds fine to me. Can you add a note to https://repo2docker.readthedocs.io/en/latest/howto/breaking_changes.html even if it's just to mention the same guide applies? Could you also post on https://discourse.jupyter.org/ so that anyone providing support for users knows there's a potential breaking change?

[weiji14]

Couple of comments:

1. Do we need to handle Ubuntu 24.04 comes with existing non-root user #1346 somehow? E.g. by overriding the default 'ubuntu' user with 'jovyan'? Or is that for downstream repos to handle?
2. There are still a few references to 'Jammy Jellyfish (22.04)' in the repo (e.g. from this search), might need to update them to 'Noble Numbat (24.04)'.

[yuvipanda]

Do we need to handle #1346 somehow?

This feels critical to test, as our new user jovyan may now have uid 1001 instead of the 1000 it used to, causing a lot of havoc in places.