Update link to CoC

Ref: #1483

Author: fhemberger

CONTRIBUTING.md

@@ -4,7 +4,7 @@
 
 The Code of Conduct explains the *bare minimum* behavior
 expectations the Node Foundation requires of its contributors.
-[Please read it before participating.](https://github.com/nodejs/node/blob/master/CODE_OF_CONDUCT.md)
+[Please read it before participating.](https://github.com/nodejs/admin/blob/master/CODE_OF_CONDUCT.md)
 
 ## Vocabulary