Update changelog for 0.3.0 release. (#43)

Author: Mike Davis

CHANGELOG.md

@@ -4,6 +4,12 @@ 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).
 
+## [0.3.0] - October 14th, 2019
+- Adds user centric API routes
+- Introduces spf13/viper based configuration
+- Adds OptlyContext middleware
+- Adds webhoook support for multiple concurrent SDK keys
+
 ## [0.2.0] - October 3rd, 2019
 - Adds Optimizely webhook support
 - Adds full Feature MGMT support