[build2] build2 Action for GitHub Workflows

[Boris Kolpackov]

Fabian Meyer via users <users at build2.org> writes:

> I just wanted to let the community know that I created a GitHub
> Workflows Action for setting up build2 with Ubuntu, and Windows
> runners.

Nice, I took a cursory look, and I have a couple of suggestions:

1. You could get rid of the hardcoded default option by downloading
   and examining https://download.build2.org/toolchain.sha256

   This file will always be there and will always be pointing to
   the latest release.

   As a bonus, you could easily make your action support the staged
   toolchain (e.g., by specifying "staged" instead of the version).
   Its toolchain.sha256: https://stage.build2.org/0/toolchain.sha256

   FYI, this is how our own CI infrastructure discovers the toolchain
   locations.

2. You can substantially speed things up by performing local installation:

   https://build2.org/install-faq.xhtml#offline

   In fact, I would probably go a step further and skip the install
   script and go directly to build2-toolchain-X.Y.Z.tar.xz (plus
   build2-baseutils on Windows) and use the build{.sh,*.bat} scripts
   inside directly (which is what the install scripts ultimately do).

Also let me know if you would be interested in transferring this project
to the github.com/build2/ organization (you will still be the owner). Then
we would be able to make it "official" GitHub action for build2 and link
to it from build2.org. Let me know if you are interested and I will send
you an invite to join the organization.