OXDEV-9641 Update CHANGELOG-v13.md

Author: hkreuter

CHANGELOG-v13.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]
+## [13.0.0] - unreleased
 
 ### Changed
 - Update module to work with OXID eShop 7.5