changelog

Signed-off-by: Peter Alfonsi <petealft@amazon.com>

Author: Peter Alfonsi

CHANGELOG.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - The dynamic mapping parameter supports false_allow_templates ([#19065](https://github.com/opensearch-project/OpenSearch/pull/19065))
 - Add a toBuilder method in EngineConfig to support easy modification of configs([#19054](https://github.com/opensearch-project/OpenSearch/pull/19054))
 - Add StoreFactory plugin interface for custom Store implementations([#19091](https://github.com/opensearch-project/OpenSearch/pull/19091))
+- Add an `item_count` metric for field data cache API ([#19174](https://github.com/opensearch-project/OpenSearch/pull/19174))
 
 ### Changed
 - Add CompletionStage variants to methods in the Client Interface and default to ActionListener impl ([#18998](https://github.com/opensearch-project/OpenSearch/pull/18998))