update changelog

Author: mna

README.md

@@ -37,6 +37,7 @@ Please note that because of the net/html dependency, goquery requires Go1.1+.
 
 **Note that goquery's API is now stable, and will not break.**
 
+*    **2018-01-11 (v1.2.0)** : Add `AddBack*` and deprecate `AndSelf` (thanks to @davidjwilkins).
 *    **2017-02-12 (v1.1.0)** : Add `SetHtml` and `SetText` (thanks to @glebtv).
 *    **2016-12-29 (v1.0.2)** : Optimize allocations for `Selection.Text` (thanks to @radovskyb).
 *    **2016-08-28 (v1.0.1)** : Optimize performance for large documents.