Update code-of-conduct.md

Author: cebe

code-of-conduct.md

@@ -61,7 +61,7 @@ the project's leadership.
 ## Attribution
 
 This Code of Conduct is adapted from the [Contributor Covenant][homepage],
-version 1.3.0, available at
+version 1.4.0, available at
 [http://contributor-covenant.org/version/1/4/][version]
 
 [homepage]: http://contributor-covenant.org