Add CHANGELOG entry for #2036

Signed-off-by: Radhakrishnan Pachyappan <gingeekrishna@gmail.com>

Author: gingeekrishna

CHANGELOG.md

@@ -23,6 +23,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Add document lifecycle guide and runnable sample ([#2017](https://github.com/opensearch-project/opensearch-java/pull/2017))
 
 ### Fixed
+- Fix `DerivedField` serializing unsupported `name` field causing `mapper_parsing_exception` ([#2036](https://github.com/opensearch-project/opensearch-java/pull/2036))
 
 ## [Unreleased 3.x]
 ### Added