Also updates the container to Debian Bookworm, because we need
its specific (patched for JDK 17) Gradle version.
Note this change makes the JavaDoc build artifact reproducible.
Currently, buildah, Podman and Docker are supported.
The goals of the reference build are:
- Make our release process more transparent
- Improve reproducibility by shielding our build from the hosts
environment
- Reduce the trust necessary for running our build by shielding
the hosts environment from possible side effects of our build
Note both the signing and the uploading of release artifacts are out
of scope for the reference build.
