Update CHANGELOG.md

Author: mehcode

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## 0.4.0 - UNRELEASED
+## 0.4.0-beta.1 - 2020-07-27
 
 ### Highlights