Zig team member here: we've migrated to Forgejo Actions [0], which is a system built into Forgejo (the Git forge used by Codeberg) which is very similar to GitHub Actions. In fact, while 1-to-1 compatibility is a non-goal, it's
almost compatible---many GHA workflows will run with minimal (or no!) changes, and most Actions written for GHA will work fine (e.g. my setup-zig Action [1] worked without changes). I don't necessarily love the design of GitHub Actions, and obviously that's all inherited in Forgejo Actions, but the issues I have with GitHub's
implementation are pretty much all solved in Forgejo (plus they're receptive to PRs if you do need to improve something!). Codeberg offer a couple of free hosted runners (x86_64-linux), though they have quite aggressive usage limits (understandably, since Codeberg can't just throw money at free compute for everyone!) so self-hosting is probably kind of necessary for big-ish projects. That's pretty easy though: the runner [2] is trivial to build (including cross-compiling) and run, and is on the whole just a much more solid piece of software, so it's already been very painless compared to what it was like to self-host GitHub's runner. On the whole, Forgejo Actions has really just felt like a much more refined and cared-for version of GitHub Actions; I'm quite happy with it so far.
[0]: https://forgejo.org/docs/latest/user/actions/reference/
[1]: https://codeberg.org/mlugg/setup-zig/
[2]: https://code.forgejo.org/forgejo/runner/