Update CHANGELOG for 1.2.0.
Update CHANGELOG for 1.2.0.

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