update CHANGELOG

Author: djnicholson

CHANGELOG.md

@@ -11,6 +11,7 @@ Check [Keep a Changelog](http://keepachangelog.com/) for recommendations on how
 - Updated C# smart contract template to provide example unit tests
 - Fixed an issue preventing contracts from being deployed to TestNet.
 - Updated Neo Express to latest RC3 build
+- Enable limited support within untrusted VS Code workspaces
 
 ## [2.1.47] - 2021-06-08