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 (on Ubuntu?).
2. Add at least one build on macOS.
3. Add a build for Alpine. Attempted in PR Added Alpine builds to GitHub Actions CI #362, but tests segmentation fault inside the GitHub Actions Alpine 3.17 container (but not in Docker on my system). Done (finally!) in PR Added Alpine builds to GitHub Actions CI #362 and PR Add Alpine 3.19 build to GitHub Actions CI #410.
4. Add at least one build on Debian. A Dockerfile for building gearmand on Debian would be helpful for this. Does anyone have one?
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.
8. At some point, change uses: actions/checkout@v3 to uses: actions/checkout@v4 since v3 is deprecated. Doing this, means we won't be able to test on old versions of gcc/Ubuntu since Node 20 won't work on those old Ubuntu versions. IMHO, we should put this off as long as possible.

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. Done in PRs #397 and #399.

[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

UPDATE: They've since been added.

[esabol]

For future reference, https://github.com/nektos/act supposedly allows you to test GitHub Actions workflows on one's local computer.