Update changelog

Author: whoseoyster

CHANGELOG.md

@@ -5,6 +5,12 @@ 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).
 
+## [Unreleased]
+
+# Changed
+
+* Deprecates `categorical_features_map` in favor of `categorical_feature_names` for model and dataset uploads.
+
 ## [0.2.0a1]
 
 ### Fixed