DOC : update changelog

- with info on recent PRs that were merged
- with note about broken `MultiContext` instance pickling on Python 2

	modified:   CHANGES.txt

Author: Poruri Sai Rahul

CHANGES.txt

@@ -1,8 +1,11 @@
 Codetools Changelog
 ===================
 
-DEV
----
+Release 4.3.0
+-------------
+
+*NOTE* : Pickling `MultiContext` instances is broken on Python 2.
+See https://github.com/enthought/codetools/issues/30 for further details.
 
 New Features
 
@@ -19,6 +22,8 @@ Enhancements
 
 Fixes
 
+* Remove deprecated traits api (#27)
+
 * Remove unused imports and dependence on `unittest2` (#13)