Update changelog

Author: mikebronner

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [0.4.22] - 17 May 2019
+### Fixed
+- issue introduce in previous release related to cache cooldown and prefixes.
+
 ## [0.4.21] - 17 May 2019
 ### Added
 - my own implementation of laravel pivot events, based on `fico7489/laravel-pivot`.