Create first community release

[zakkak]

We need to:

• tag latest commit in branch 20 (so we have to decide the tagging scheme we plan to follow)
• release a mandrel tarball

[ppalaga]

Builds for which platforms will be available?

[zakkak]

Hello @ppalaga, at the moment we are planning to release tarballs only for amd64

[zakkak]

Blocked on #39 and #41

[zakkak]

Currently blocked by #38

[Xaseron]

Can you also provide a container image like https://hub.docker.com/r/oracle/graalvm-ce?

[Karm]

Hello @Xaseron,
there will be a Quarkus builder image based on Mandrel.

[ppalaga]

Time to close this one? https://github.com/graalvm/mandrel/releases/tag/mandrel-20.1.0.0.Alpha1