Update CHANGELOG.md
Update CHANGELOG.md

Added version 0.5.2
hartz89/restangular,scalp42/restangular,aychando/restangular,marciocamello/restangular,kevinrenskers/restangular,yelmontaser/restangular,dokkis/restangular,Akallabet/restangular,bartzilla/restangular,ackimwilliams/restangular,hansottowirtz/restangular,chacbumbum/restangular,fernandomoraes/restangular,xuwupeng2000/restangular,sergiocruz/restangular,mgonto/restangular,janeyhjy/restangular,facingsouth/restangular,zhengcongzhen/restangular,rodrigomf24/restangular,matiomlei/restangular-1,duxet/restangular,cruiser/restangular,Nihaux/restangular,arabianfoz/restangular,sesubash/restangular,idpaterson/restangular,CandyLee198088/restangular,mrahhal/restangular,jsdevel/restangular,dshefchik/restangular,dankahle/restangular