chore: Update changelog

Author: siegfriedweber

CHANGELOG.md

@@ -17,6 +17,9 @@ All notable changes to this project will be documented in this file.
   - PodDisruptionBudgets
   - Replicas
 - Add Listener support ([#17]).
+- Make the environment variables `OPENSEARCH_HOME` and `OPENSEARCH_PATH_CONF` overridable, so that
+  images can be used which have a different directory structure than the Stackable image ([#18]).
 
 [#10]: https://github.com/stackabletech/opensearch-operator/pull/10
 [#17]: https://github.com/stackabletech/opensearch-operator/pull/17
+[#18]: https://github.com/stackabletech/opensearch-operator/pull/18