Add a changelog to document user-facing changes

Author: HeikoBecker

CHANGELOG.md

@@ -0,0 +1,6 @@
+# Changelog
+
+All notable changes to this project are documented in this file.
+
+Format of the log is _loosely_ based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/). 
+The project does _not_ follow Semantic Versioning and the changes are documented in reverse chronological order, grouped by calendar month.