Adding changes to change log.

Author: rhysrevans3

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Changed
 
+- Extended Datetime Search to search on start_datetime and end_datetime as well as datetime fields. [#182](https://github.com/stac-utils/stac-fastapi-elasticsearch/pull/182)
+
 - Elasticsearch drivers from 7.17.9 to 8.11.0 [#169](https://github.com/stac-utils/stac-fastapi-elasticsearch/pull/169)
 
 ### Fixed