pom.xml: updates for release 0.143.25
pom.xml: updates for release 0.143.25

Update killbill-api -> 0.53.8 & killbill-client -> 1.1.5

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

killbill/killbill-oss-parent