Add entry to CHANGELOG

Author: jamescdavis

CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) a
 
 ## [Unreleased]
 
+### Added
+
+* Blueprint (and tests) to generate in-repo addons configured for TypeScript
+
 ### Changed
 
 * Improve instructions for setting up [Linked Addons](README.md#linking-addons) and [In-repo Addons](README.md#in-repo-addons).