pom.xml: updates for release 0.5.1
pom.xml: updates for release 0.5.1

Add expiration period property for pending 3DS payments

Signed-off-by: Kill Bill core team <1a73af9e7ae00182733b2292511b814be66f065f@killbill.io>

killbill/killbill-adyen-plugin,andrenpaes/killbill-adyen-plugin