That's basically the same thing that I'm doing in mine though I didn't know about the latest.php script at amxmodx.org. I'm more used to Jenkins and I was looking for a way to upload an artifact to the workflow itself like Jenkins has and it looks like that's what you are doing (GitHub Actions are entirely new to me).
I spent some time and updated mine (found
here) with inspiration from rtxa's version. Mine now compiles all plugins in your scripting folder and it uploads the compiled plugins as
an artifact that you can download from
the workflow run page. You can easily change the AMX Mod X version (only works for 1.9 and 1.10 currently), the scripting folder location in your repo, and if you want it to download the mod-specific files, all via three environment variables.
Note that the default life of artifacts is 90 days. If you want to make them more permanent, you'll need to create a release.