Adds CHANGELOG entry for #51

Author: weierophinney

CHANGELOG.md

@@ -4,11 +4,12 @@ All notable changes to this project will be documented in this file, in reverse
 
 Versions prior to 0.4.0 were released as the package "weierophinney/hal".
 
-## 1.2.0 - TBD
+## 1.2.0 - 2018-12-11
 
 ### Added
 
-- Nothing.
+- [#51](https://github.com/zendframework/zend-expressive-hal/pull/51) adds support for zend-hydrator version 3 releases. You may continue to use
+  version 2 releases as well.
 
 ### Changed