Fix changelog

Signed-off-by: John Mazanec <[email protected]>

Author: jmazanec15

CHANGELOG-3.0.md

@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Change priority for scheduling reroute during timeout([#16445](https://github.com/opensearch-project/OpenSearch/pull/16445))
 - Renaming the node role search to warm ([#17573](https://github.com/opensearch-project/OpenSearch/pull/17573))
 - Introduce a new search node role to hold search only shards ([#17620](https://github.com/opensearch-project/OpenSearch/pull/17620))
+- Add dfs transformation function in XContentMapValues ([#17612](https://github.com/opensearch-project/OpenSearch/pull/17612))
 
 ### Dependencies
 - Bump `ch.qos.logback:logback-core` from 1.5.16 to 1.5.17 ([#17609](https://github.com/opensearch-project/OpenSearch/pull/17609))