Update changelog

CHANGELOG.md

@@ -1,7 +1,15 @@
 # Change Log
-All notable changes to the "jsonnet" extension will be documented in this file.
+All notable changes to the "Jsonnet NG" extension will be documented in this file.
 
 Check [Keep a Changelog](http://keepachangelog.com/) for recommendations on how to structure this file.
 
-## [Unreleased]
-- Initial release
+## [1.0.0] 2021-04-27
+## Added
+- VSCode extension icon
+- Icon for jsonnet file extensions
+
+### Changed
+- Change preview from deprecated and removed `vscode.previewHtml` command to the new Webview based panel
+
+## [0.1.0] 2018-04-14
+- Initial release