docs(changelog): add the app package cleanup to 0.1.5

Assisted-by: Claude Code:claude-opus-5-5
Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

Author: AndyScherzinger

CHANGELOG.md

@@ -18,6 +18,9 @@ All notable changes to this project will be documented in this file.
 - fix(viewer): load the stylesheet of a legacy theme into the editor again, so admins can restyle it [#433](https://github.com/nextcloud/files_mindmap/pull/433)
 - fix(viewer): translate the editor's messages [#447](https://github.com/nextcloud/files_mindmap/pull/447)
 
+### Other
+- build(appstore): leave development files out of the app package [#453](https://github.com/nextcloud/files_mindmap/pull/453)
+
 ## 0.1.4
 
 ### Added