PR C of three, and the last of the stage-2 sequence. Same chart as
1.0.0+upjava8 and 1.0.0+upjava17, published for the third Java line, so
main comes to rest on the line of the only server that is actually
running.
minecraft.version moves with it (1.20.1 -> 1.21.1): a Minecraft version
only runs on a matching JVM, and 1.20.5+ needs Java 21. This default now
equals what ftb-skies-2 sets in its own values file, so the install-test
boots the production version rather than an arbitrary Java-21-capable one.
The CI values deliberately do not override minecraft.version, so this
default is what the install-test exercises.
jklein
fd5692cac7