Upgrade the deprecated `ubuntu-20` builders in CI

[jpraynaud]

Why

GitHub runners ubuntu-20 will be deprecated on 02/01/25 and removed on 04/01/2025 (as explained in actions/runner-images#11101). This means that we will not be able to support the Glibc 2.31 in the pre-built binaries, and that the minimum supported version will be 2.35.

What

We want to properly handle the transition with our users by announcing the modification in advance and proceed to the upgrade to unbuntu-22+ runners for the CI.

How

• Mid January:
  • Update the Linux Requirements section of the release notes to announce the upcoming deprecation and removal
  • Update the Linux Requirements in the website and READMEs
  • Discord announcement
  • Slack announcements
  • Create a new dev blog post
  • Update the one line installer to display a warning (automatically if possible, or for Linux users only)
  • Update all the ubuntu-22 to ubuntu-24
• Mid February:
  • Bump the runner used to build binaries for Linux to ubuntu-22
  • Update the Linux Requirements section of the release notes
  • Update the Linux Requirements in the website and README