Update changlog

Signed-off-by: Asim Mahmood <asim.seng@gmail.com>

Author: asimmahmood1

CHANGELOG.md

@@ -6,7 +6,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ## [Unreleased 2.x]
 ### Added
 - Improve performace of NumericTermAggregation by avoiding unnecessary sorting([#17252](https://github.com/opensearch-project/OpenSearch/pull/17252))
-- Add execution_hint to cardinality aggregator request (#[TBD](TBD))
+- Add execution_hint to cardinality aggregator request (#[17419](https://github.com/opensearch-project/OpenSearch/pull/17419))
 
 ### Dependencies
 - Bump `dnsjava:dnsjava` from 3.6.2 to 3.6.3 ([#17231](https://github.com/opensearch-project/OpenSearch/pull/17231))