pom.xml: updates for release 0.47
pom.xml: updates for release 0.47

Update killbill-client -> 0.12

Signed-off-by: stephane brossier <c1fb28815da1df8a6921017a648d6c4b5d859b78@groupon.com>

maguero/killbill-oss-parent,rocketlawyer/killbill-oss-parent,killbill/killbill-oss-parent