Update gemspec with dependency on ripper_ruby_parser.
Update gemspec with dependency on ripper_ruby_parser.

troessner/reek,skywinder/reek,HParker/reek,apuratepp/reek,HParker/reek,weby/reek,HParker/reek,apuratepp/reek,troessner/reek,nTraum/reek,andyw8/reek,skywinder/reek,nTraum/reek,tansaku/reek,andyw8/reek,skywinder/reek,tansaku/reek,tansaku/reek,andyw8/reek,weby/reek,weby/reek,chastell/reek,apuratepp/reek