Update RSpec dependency
Update RSpec dependency

Specs don't work with rspec-mocks 2.12.0 due to an issue with
setting expectations on `.decorate` - rspec/rspec-mocks#206

mallikarjunayaddala/draper,chuck-john/draper,drapergem/draper,Bastes/draper,drapergem/draper,baberthal/draper,outstand/draper,sideci-sample/sideci-sample-draper,SpencerCDixon/draper,estum/draper,chuck-john/draper,yui-knk/draper,krainboltgreene/draper,Bastes/draper,drapergem/draper,mallikarjunayaddala/draper,jianyuan/draper,totzyuta/draper,estum/draper,baberthal/draper,yui-knk/draper,turingschool/draper,totzyuta/draper,liwangbest/draper,outstand/draper,donaldpiret/draper,liwangbest/draper,SpencerCDixon/draper,jianyuan/draper,turingschool/draper