add a missing changelog entry for #368

Author: pierreglaser

Diff for: CHANGES.md

@@ -9,6 +9,10 @@
   Python 3.6 and 3.7.
   ([PR #370](https://github.com/cloudpipe/cloudpickle/pull/370))
 
+- Internal refactoring to ease the use of `pickle5` in cloudpickle
+  for Python 3.6 and 3.7.
+  ([PR #368](https://github.com/cloudpipe/cloudpickle/pull/368))
+
 
 1.4.1
 =====