Drop Python 3.7 support

[johnthagen]

Our CI ubuntu version was pinned lower to ubuntu-22.04 in

• Support Python 3.13, add Django 5.1 trove classifier, and fix Python 3.7 CI #543

This is because we cannot drop Python 3.7 due to waiting on a JazzBand admin to migrate us back to our GitHub organization

• Transfer Out: django-dbbackup jazzband/help#336

After we transfer out and drop Python 3.7 support, we should bump the Ubuntu version back up to ubuntu-24.04.

[johnthagen]

@Archmonger could you change the settings on this repo to remove Python 3.7 and 3.8 from required checks (since both are end of life)?

Perhaps we simply remove all required checks to avoid this issue in the future. We can still only merge if things are green, but the GitHub project wouldn't enforce it.

[Archmonger]

Agreed, if it's just us two as admins then there's no need for GitHub Required Checks.

It has been disabled.