Update CHANGELOG.md

Author: mlojewski-me

CHANGELOG.md

@@ -5,6 +5,8 @@ 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).
 
 ## [Unreleased]
+### Added
+- Options for Courier authlib authentication: courier_md5, courier_md5raw, courier_sha1, courier_sha256
 
 ## [3.1.0] - 2018-02-06
 ### Added