Update CHANGELOG
Update CHANGELOG

xjzhou/PyMySQL,xjzhou/PyMySQL,lzedl/PyMySQL,wraziens/PyMySQL,eibanez/PyMySQL,modulexcite/PyMySQL,boneyao/PyMySQL,pymysql/pymysql,yeyinzhu3211/PyMySQL,lzedl/PyMySQL,DashaChuk/PyMySQL,PyMySQL/PyMySQL,yeyinzhu3211/PyMySQL,Ting-y/PyMySQL,MartinThoma/PyMySQL,wraziens/PyMySQL,nju520/PyMySQL,jheld/PyMySQL,methane/PyMySQL,eibanez/PyMySQL,NunoEdgarGub1/PyMySQL,anson-tang/PyMySQL