Update default dev ruby version to 2.3.1
Update default dev ruby version to 2.3.1

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