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).
 
-## [0.3.0] - 2018-10-30
+## [0.3.1] - 2018-10-30
 ### Changed
 - Moved URDFExporter.js file to `src` folder.
 - Added UMD variant of URDFExporter to `umd` folder.