Added changelog entry

Author: michalChrobot

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -28,6 +28,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Fixed
 
+- Fixed memory leak in `NetworkAnimator` on clients where `RpcTarget` groups were not being properly disposed due to incorrect type casting of `ProxyRpcTargetGroup` to `RpcTargetGroup`.
 - 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)
 

com.unity.netcode.gameobjects/Runtime/Components/NetworkAnimator.cs

@@ -933,7 +933,6 @@ public override void OnNetworkSpawn()
             {
                 Send = new RpcSendParams()
                 {
-                    // FIX: Use m_TargetGroup.Target to get the BaseRpcTarget
                     Target = m_TargetGroup?.Target
                 }
             };