Use CI to run tests

[ianprime0509]

It would be nice to have CI set up to run tests and make sure things keep working without manually testing each commit. The best way to do this would be to use the GNOME SDK Flatpaks, as this is also the recommended development environment, but that will be more difficult to manage until Zig 0.12 is tagged, as there is no Zig master Freedesktop SDK extension (and I'm not sure I want to take on the responsibility of maintaining one).