release.sh: change groupId to org.kill-bill.billing.plugin.ruby
release.sh: change groupId to org.kill-bill.billing.plugin.ruby

Signed-off-by: Pierre-Alexandre Meyer <ff019a5748a52b5641624af88a54a2f0e46a9fb5@mouraf.org>

killbill/killbill-hello-world-ruby-plugin,killbill/killbill-hello-world-ruby-plugin