Switch java versioning scheme to SNAPSHOTs before release

While the java variant previously had SNAPSHOT builds after the
release (like

  x -> x-SNAPSHOT -> (x+1) -> (x+1)-SNAPSHOT

), the Java world typically has SNAPSHOT builds before the release
(like

  x-SNAPSHOT -> x -> (x+1)-SNAPSHOT -> (x+1)

). We bump to a new unencumbered version, to be able to switch to the
usual Java versioning scheme.