Additional refinements to GitHub Actions CI workflow

[esabol]

Now that PR #334 has been merged, I'd like to see the following enhancements to the GitHub Actions CI workflow:

1. Add builds for different versions of clang.
2. Add at least one build on macOS.
3. Add a build for Alpine 3.17, which uses gcc 12. Attempted in PR Draft: Added Alpine 3.17/gcc 12 build to GitHub Actions CI #362, but tests segmentation fault inside the GitHub Actions Alpine 3.17 container (but not in Docker on my system).
4. Maybe add at least one build on Debian? A Dockerfile for building gearmand on Debian would be helpful for this.
5. Rename the .github/workflow/c-cpp.yml file to the far more common name ci.yml. Done in PR More refinements to GitHub Actions CI #363.
6. Change uses: actions/checkout@v2 to uses: actions/checkout@v3 (or uses: actions/checkout@main to always use the latest checkout action?) to eliminate the Node.js 12 actions are deprecated. warning we are now getting. Done in PR Update actions/checkout to v3 in GitHub Actions CI workflow #360.
7. Add CXXFLAGS="-Wp,-D_GLIBCXX_ASSERTIONS" to the gcc 9 (and higher??) build(s). Done in PR Added CXXFLAGS="-Wp,-D_GLIBCXX_ASSERTIONS" to gcc-9 and higher builds in GitHub Actions CI #361.

If anyone wants to help with these, I'd appreciate it!

[esabol]

Ubuntu 24.04 is out, so probably should add that to the CI. Also new versions of gcc have been released as well.

[esabol]

Ubuntu 24.04 is out, so probably should add that to the CI.

Apparently, GitHub hasn't added Ubuntu 24.04 runners yet. I'm surprised.

github/roadmap#958

So I think we need to use a container instead:

https://github.com/actions/runner-images