Fix Contributor Covenant link definition reference in attribution section (#5762)

Author: IamLizu

Code-Of-Conduct.md

@@ -127,7 +127,7 @@ project community.
 
 ## Attribution
 
-This Code of Conduct is adapted from the [Contributor Covenant, version 2.0](cc-20-doc).
+This Code of Conduct is adapted from the [Contributor Covenant, version 2.0][cc-20-doc].
 
 Community Impact Guidelines were inspired by
 [Mozilla's code of conduct enforcement ladder](https://github.com/mozilla/diversity).