feat(generalsio): read game updates

The game state saved in `map` and `cities` is initialized to an empty
array. I am thinking that the patch method would at the first iteration
push new items to an empty array. Although I am not sure whether it is
the best approach as patch method should not have an if checking if it
is the first time the patch function is called. Maybe we could create
init function that would be called on the first update only?

Ideally we would initialize the game states to appropriate size,
unfortunatelly, sizes are propagated with the first `game_update`. If we
used Python list then we don't have this problem as Python slices would
handle that for us. Could numpy slice work as well?

generals/remote/generalsio_client.py

@@ -1,3 +1,4 @@
+import numpy as np
 from socketio import SimpleClient  # type: ignore
 
 from generals.agents.agent import Agent
@@ -96,12 +97,20 @@ def _play_game(self, agent_index: int) -> None:
         :param agent_index: The index of agent in the game
         """
         winner = False
+        map = np.empty([])  # noqa: F841
+        cities = np.empty([])  # noqa: F841
+        # TODO deserts?
         while True:
-            event = self.receive()[0]
-            if event == "game_lost" or event == "game_won":
-                # server sends game_lost or game_won before game_over
-                winner = event == "game_won"
-                break
+            event, data, suffix = self.receive()
+            print('received an event:', event)
+            match event:
+                case "game_update":
+                    map_diff = np.array(data["map_diff"])  # noqa: F841
+                    cities_diff = np.array(data["cities_diff"])  # noqa: F841
+                case "game_lost" | "game_won":
+                    # server sends game_lost or game_won before game_over
+                    winner = event == "game_won"
+                    break
 
         self._finish_game(winner)