Add PR number to CHANGELOG entry

Author: simon-lemay-unity

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -22,7 +22,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Fixed
 
-- Fixed an issue in `UnityTransport` where the transport would accept sends on invalid connections, leading to a useless memory allocation and confusing error message.
+- Fixed an issue in `UnityTransport` where the transport would accept sends on invalid connections, leading to a useless memory allocation and confusing error message. (#3382)
 - Fixed issue where the time delta that interpolators used would not be properly updated during multiple fixed update invocations within the same player loop frame. (#3355)
 - Fixed issue when using a distributed authority network topology and many clients attempt to connect simultaneously the session owner could max-out the maximum in-flight reliable messages allowed, start dropping packets, and some of the connecting clients would fail to fully synchronize. (#3350)
 - Fixed issue when using a distributed authority network topology and scene management was disabled clients would not be able to spawn any new network prefab instances until synchronization was complete. (#3350)