bump version to 0.4.0 (#33)

Author: Acepie

CHANGELOG.md

@@ -5,6 +5,8 @@ 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]
+
+## [0.4.0] - 2021-06-28
 ### Added
 * Git information is now stored in a postgreSQL database on project creation