Add changelog

Signed-off-by: Liyun Xiu <xiliyun@amazon.com>

CHANGELOG.md

@@ -72,6 +72,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Fix create or update alias API doesn't throw exception for unsupported parameters ([#14719](https://github.com/opensearch-project/OpenSearch/pull/14719))
 - Refactoring FilterPath.parse by using an iterative approach ([#14200](https://github.com/opensearch-project/OpenSearch/pull/14200))
 - Refactoring Grok.validatePatternBank by using an iterative approach ([#14206](https://github.com/opensearch-project/OpenSearch/pull/14206))
+- Fix NPE when creating index with index.number_of_replicas set to null ([#14812](https://github.com/opensearch-project/OpenSearch/pull/14812))
 - Update help output for _cat ([#14722](https://github.com/opensearch-project/OpenSearch/pull/14722))
 - Fix bulk upsert ignores the default_pipeline and final_pipeline when auto-created index matches the index template ([#12891](https://github.com/opensearch-project/OpenSearch/pull/12891))