pom.xml: fix groupId for Ning's maven plugins
pom.xml: fix groupId for Ning's maven plugins

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

maguero/killbill-oss-parent,rocketlawyer/killbill-oss-parent,killbill/killbill-oss-parent,aeq/killbill-oss-parent,kares/killbill-oss-parent,andrenpaes/killbill-oss-parent