Update ubuntu-latest to 24.04

[rafl]

To match the github runner images.

The current situation, where ubuntu-latest refers to ubuntu-22.04, is a little confusing and can make debugging certain CI problems much harder.

[colin-i]

There is a catthehacker/ubuntu:act-24.04 tag on docker. Edit: you are right act-latest is pointing to act-22.04.

[colinmollenhour]

Quickie for anyone else just trying this out:

❯ gh act push -P ubuntu-latest=catthehacker/ubuntu:act-24.04