Update CONTRIBUTING.md (#5257)
Update CONTRIBUTING.md (#5257)


yangwenmai/tidb,CodeRushing/tidb,EvilMcJerkface/tidb,EvilMcJerkface/tidb,ngaut/tidb,XuHuaiyu/tidb,cosmtrek/tidb,qiuyesuifeng/tidb,mccxj/tidb,Nify/tidb,Cofyc/tidb,ngaut/tidb,cosmtrek/tidb,kyle-wang/tidb,pingcap/tidb,kyle-wang/tidb,c4pt0r/tidb,ming-relax/tidb,ngaut/tidb,Nify/tidb,ngaut/tidb,kyle-wang/tidb,ngaut/tidb,CodeRushing/tidb,wusphinx/tidb,pingcap/tidb,Cofyc/tidb,wusphinx/tidb,c4pt0r/tidb,coocood/tidb,ngaut/tidb,spongedu/tidb,XuHuaiyu/tidb,tiancaiamao/tidb,pingcap/tidb,c4pt0r/tidb,c4pt0r/tidb,ming-relax/tidb,kyle-wang/tidb,spongedu/tidb,kyle-wang/tidb,kyle-wang/tidb,tiancaiamao/tidb,pingcap/tidb,pingcap/tidb,mccxj/tidb,c4pt0r/tidb,coocood/tidb,yangwenmai/tidb,qiuyesuifeng/tidb,c4pt0r/tidb,pingcap/tidb