Core/Misc: Fix GCC 8 warnings

src/server/game/Entities/GameObject/GameObject.cpp

@@ -433,6 +433,7 @@ void GameObject::Update(uint32 diff)
             }
             // NO BREAK for switch (m_lootState)
         }
+        /* fallthrough */
         case GO_READY:
         {
             if (m_respawnCompatibilityMode)