update changelog

Author: jonhealy1

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 
 - Collection-level Assets to the CollectionSerializer [#148](https://github.com/stac-utils/stac-fastapi-elasticsearch/issues/148)
+- Pagination for /collections - GET all collections - route [#164](https://github.com/stac-utils/stac-fastapi-elasticsearch/pull/164)
 
 ### Added