Update changelog

Author: noellie-velez

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -14,7 +14,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 - `NetworkTransport.EarlyUpdate` and `NetworkTransport.PostLateUpdate` are now public. For the vast majority of users, there's really no point in ever calling those methods directly (the `NetworkManager` handles it). It's only useful if wrapping transports outside of NGO. (#3890)
 
 ### Changed
-
+- Improve performance of `NetworkRigidbodyBase`. (#3906)
 
 ### Deprecated