doc: fixed invalid url in CONTRIBUTORS.md (#13703)
doc: fixed invalid url in CONTRIBUTORS.md (#13703)


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