Update changelog

Author: gkjohnson

CHANGELOG.md

@@ -4,7 +4,7 @@ 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).
 
-## Unreleased
+## [0.2.0] - 2018-08-23
 ### Changed
 - Moved `robotName` from an option in the `parse` function to an option.
 - URDF contents are now in the `data` field instead of the `urdf` field.