Updated CHANGELOG

Author: thijskok

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/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [1.2.0] - 2021-01-07
+### Added
+- Guzzle 7 support
+
 ## [1.1.0] - 2020-05-06
 ### Updated
 - Updated composer.json namespace to comply with PSR-4