Update changelog

Author: ddeboer

CHANGELOG.md

@@ -6,13 +6,12 @@ See also the [GitHub releases page](https://github.com/FriendsOfSymfony/FOSHttpC
 2.0.0 (unreleased)
 ------------------
 
-* Decoupled from the Guzzle HTTP client.
+* Replace hard coupling on Guzzle HTTP client with HTTP adapter.
 * The NGINX purge location is no longer passed as constructor argument but by
   calling `setPurgeLocation()`.
 * In ProxyTestCase, `getHttpClient()` has been replaced with `getHttpAdapter()`;
   added HTTP method parameter to `getResponse()`.
 
-
 1.4.0
 -----