doc: update README code of conduct (#1553)

Co-authored-by: Binbin Li <[email protected]>

README.md

@@ -49,13 +49,7 @@ Meeting notes for weekly project syncs can be found [here](https://hackmd.io/ABu
 
 ## Code of Conduct
 
-This project has adopted the [Microsoft Open Source Code of
-Conduct](https://opensource.microsoft.com/codeofconduct/).
-
-For more information see the [Code of Conduct
-FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or contact
-[[email protected]](mailto:[email protected]) with any additional
-questions or comments.
+Ratify follows the [CNCF Code of Conduct](https://github.com/cncf/foundation/blob/master/code-of-conduct.md).
 
 ## Release Management