Update changelog.md

Author: beanieboi

changelog.md

@@ -4,7 +4,7 @@ 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).
 
-## [unreleased] - 2020-05-05
+## [1.4] - 2020-05-05
 ### Added
 - [all] add nginx-debug binary
 - [heroku-20] add support for Heroku-20