README.md: Update URL to MySQL compatibility information (#11821)
README.md: Update URL to MySQL compatibility information (#11821)


pingcap/tidb,ngaut/tidb,kyle-wang/tidb,Cofyc/tidb,c4pt0r/tidb,XuHuaiyu/tidb,cosmtrek/tidb,pingcap/tidb,pingcap/tidb,ngaut/tidb,coocood/tidb,pingcap/tidb,qiuyesuifeng/tidb,c4pt0r/tidb,XuHuaiyu/tidb,cosmtrek/tidb,EvilMcJerkface/tidb,kyle-wang/tidb,pingcap/tidb,c4pt0r/tidb,coocood/tidb,ngaut/tidb,EvilMcJerkface/tidb,c4pt0r/tidb,ngaut/tidb,qiuyesuifeng/tidb,c4pt0r/tidb,pingcap/tidb,ming-relax/tidb,kyle-wang/tidb,ngaut/tidb,kyle-wang/tidb,Cofyc/tidb,ming-relax/tidb,ngaut/tidb,kyle-wang/tidb,c4pt0r/tidb,kyle-wang/tidb