Prepare changelog for next release

Author: tomvanmele

CHANGELOG.md

@@ -5,6 +5,15 @@ 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
+
+### Added
+
+### Changed
+
+### Removed
+
+
 ## [0.2.1] 2024-05-15
 
 ### Added