Updated CHANGELOG

Author: tgeens

CHANGELOG.md

@@ -5,7 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## _Unreleased_
+## 0.3.0 - 2021-12-09
+
+Fixed:
+
+* [#4] - OPA client can now serialize `java.time` classes as `input` 
+
+[#4]: https://github.com/xenit-eu/opa-java-client/pull/4
 
 ## 0.2.0 - 2021-07-20