Update CHANGELOG.md

Author: Andrzej Pijanowski

CHANGELOG.md

@@ -9,7 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Added
 
-- Added retry with back-off logic for Redis related functions.
+- Added retry with back-off logic for Redis related functions. [#528](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/528)
 
 ### Changed