Updated CHANGELOG

Author: oscarotero

CHANGELOG.md

@@ -4,6 +4,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/) 
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## UNRELEASED
+
+### Changed
+
+* Append `.dist` suffix to phpcs.xml and phpunit.xml files
+* Changed the configuration of phpcs and php_cs
+* Upgraded phpunit to the latest version and improved its config file
+
 ## 0.3.0 - 2016-12-26
 
 ### Changed