chore: Fix changelog headings

Author: NickLarsenNZ

CHANGELOG.md

@@ -18,10 +18,6 @@
 - Use `json` file extension for log files ([#647]).
 - Fix a bug where changes to ConfigMaps that are referenced in the HbaseCluster spec didn't trigger a reconciliation ([#645]).
 
-### Fixed
-
-- Use `json` file extension for log files ([#647]).
-
 [#640]: https://github.com/stackabletech/hbase-operator/pull/640
 [#645]: https://github.com/stackabletech/hbase-operator/pull/645
 [#647]: https://github.com/stackabletech/hbase-operator/pull/647