Prepare the next CHANGELOG

Author: williamdes

CHANGELOG.md

@@ -5,6 +5,8 @@ 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] - yyyy-mm-dd
+
 ## [5.5.4] - 2023-12-16
 
 - Fix PHP 8.2 dynamic properties for configurations with the `language` key