chore: bump changelog

Author: Elliott Marquez

CHANGELOG.md

@@ -4,8 +4,9 @@ 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/).
 
-## Unreleased
+<!-- ## Unreleased -->
 
+## [v0.20.0] - 2020-12-03
 ### Changed
 
 - `ripple_directive`