Bump version to 2.1.5.
Bump version to 2.1.5.

duanhjlt/FontAwesomeKit,LiuDeng/FontAwesomeKit,emodeqidao/FontAwesomeKit,wjszf/FontAwesomeKit,Suninus/FontAwesomeKit,GabrielCartier/FontAwesomeKit,bulusoy/FontAwesomeKit,lijie121210/FontAwesomeKit,ichu501/FontAwesomeKit,Pingco/FontAwesomeKit,hanhailong/FontAwesomeKit,keyboardsamurai/FontAwesomeKit,pengleelove/FontAwesomeKit,iwakevin/FontAwesomeKit,patelmayank/FontAwesomeKit,nsantorello/FontAwesomeKit,modulexcite/FontAwesomeKit,hejunbinlan/FontAwesomeKit,Navirize/FontAwesomeKit,hanangellove/FontAwesomeKit,PrideChung/FontAwesomeKit,BlessNeo/FontAwesomeKit,jonesgithub/FontAwesomeKit,msdgwzhy6/FontAwesomeKit