Updated changelog

Author: dancannon

CHANGELOG.md

@@ -15,6 +15,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ## Changed
 
 - Exported the `Build()` function on `Query` and `Term`.
+- Updated import of `github.com/cenkalti/backoff` to `github.com/cenk/backoff`
 
 ## v2.0.4 - 2016-05-22