update zh_CN translation
update zh_CN translation

emersion/geary,githubnemo/geary,glebihan/geary,AtticHacker/geary,martinra/geary,mjog/geary,mjog/geary,glebihan/geary,tshikaboom/geary,glebihan/geary,rschroll/geary,githubnemo/geary,aatishnn/geary,robol/geary,emersion/geary,tshikaboom/geary,githubnemo/geary,MohamedIM/geary-unofficial,mpdeimos/geary,robol/geary,AtticHacker/geary,aatishnn/geary,martinra/geary,AtticHacker/geary,martinra/geary,emersion/geary,jimbonator/geary,tshikaboom/geary,rschroll/geary,mjog/geary,aatishnn/geary,robol/geary,geekvigilante/geary,jimbonator/geary,jimbonator/geary