add changelog entry

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

Author: mch2

CHANGELOG.md

@@ -37,6 +37,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Cannot communicate with HTTP/2 when reactor-netty is enabled ([#18599](https://github.com/opensearch-project/OpenSearch/pull/18599))
 - Fix the visit of sub queries for HasParentQuery and HasChildQuery ([#18621](https://github.com/opensearch-project/OpenSearch/pull/18621))
 
+- Fix Replication lag computation ([#18602](https://github.com/opensearch-project/OpenSearch/pull/18602))
 
 ### Security
 

server/src/main/java/org/opensearch/indices/replication/SegmentReplicator.java

@@ -32,9 +32,9 @@
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
-import java.util.List;
 import java.time.Duration;
 import java.time.Instant;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.ConcurrentNavigableMap;