Github Action CI pipeline

[Giuseppe Barbieri]

Hi,

I'm interested in the panama project (foreign branch actually) and given my
background with Gradle, I also got myself into a plugin to easier and
smooth the usage of jextract for us (lib) devs.

I played with the current implementation for Github Action in the last days
(https://github.com/elect86/panama-foreign) it's quite elaborate and
complex, almost ready to be used, but I think it's not enabled on the
corresponding repo.

Moreover all the tasks were failing because of a missing clang/llvm (fixed
just linux/macos 64 but not all the other ones).

Anyway, I do have a couple ideas about how to enhance it, I tried to talk
about them on the panama ML (
https://mail.openjdk.java.net/pipermail/panama-dev/2021-June/014170.html),
but Maurizio said that wasn't the right place and he suggested me this ML,
so here I am :)

My first wish is every day to build (and publish) a nightly if all the
tests pass. In this way, the jextract gradle plugin (I mentioned above)
would be able to just grab it and make it available locally whenever I want

I can probably do it in a couple of days on my fork, but I think it'd be
nice to do everything upstream and officially (also my GH Action fu is not
so strong :p and we might fix the rest of the platforms) so that many
others may benefit from this

What do you think guys?


Giuseppe