update travis build to use later version of JDK
update travis build to use later version of JDK

DiUS/pact-jvm,DiUS/pact-jvm,algra/pact-jvm,algra/pact-jvm,olga-vasylchenko/pact-jvm,Fitzoh/pact-jvm,Fitzoh/pact-jvm,flaregames/pact-jvm