update changelog

Author: philippotto

CHANGELOG.unreleased.md

@@ -24,6 +24,7 @@ For upgrade instructions, please check the [migration guide](MIGRATIONS.released
 ### Fixed
 - Fixed that layer bounding boxes were sometimes colored green even though this should only happen for tasks. [#8535](https://github.com/scalableminds/webknossos/pull/8535)
 - Fixed that annotations could not be opened anymore (caused by #8535). [#8599](https://github.com/scalableminds/webknossos/pull/8599)
+- Voxels outside of the layer bounding box cannot be brushed, anymore. [#8602](https://github.com/scalableminds/webknossos/pull/8602)
 
 ### Removed