Update CHANGELOG

Author: EmandM

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -28,6 +28,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Fixed
 
+- Duplicate transport connection events for the same connection will now do nothing. (#3863)
 - Fixed issue when using a client-server topology where a `NetworkList` with owner write permissions was resetting sent time and dirty flags after having been spawned on owning clients that were not the spawn authority. (#3850)
 - Fixed an integer overflow that occurred when configuring a large disconnect timeout with Unity Transport. (#3810)