Prepare release

Signed-off-by: Andy Lo-A-Foe <andy.loafoe@gmail.com>

Author: loafoe

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## v2.1.0
+
+- Add `pre_commands` argument (#43)
+
 ## v2.0.1
 
 - Always validate on create (#40)