Update to ruby 2.3.1 in travis
Update to ruby 2.3.1 in travis

bethesque/pact_broker,ThePletch/pact_broker,tancnle/pact_broker,ThePletch/pact_broker,tancnle/pact_broker,pact-foundation/pact_broker,ThePletch/pact_broker,ThePletch/pact_broker,bethesque/pact_broker,bethesque/pact_broker,pact-foundation/pact_broker,pact-foundation/pact_broker,tancnle/pact_broker,pact-foundation/pact_broker,bethesque/pact_broker,tancnle/pact_broker