Update CEPC reference to CoC

That's the new name of the document

Author: frivoal

CODE_OF_CONDUCT.md

@@ -2,4 +2,4 @@
 
 This repository, being work of the 
 [World Wide Web Consortium (W3C)](https://www.w3.org/), is subject to the 
-[W3C Code of Ethics and Professional Conduct](https://www.w3.org/Consortium/cepc/).
+[W3C Code of Conduct](https://www.w3.org/policies/code-of-conduct/).