Take Counter back out of RestrictedUnpickler

Utils.py

@@ -441,9 +441,6 @@ class RestrictedUnpickler(pickle.Unpickler):
     def find_class(self, module: str, name: str) -> type:
         if module == "builtins" and name in safe_builtins:
             return getattr(builtins, name)
-        # used by OptionCounter
-        if module == "collections" and name == "Counter":
-            return collections.Counter
         # used by MultiServer -> savegame/multidata
         if module == "NetUtils" and name in {"NetworkItem", "ClientStatus", "Hint",
                                              "SlotType", "NetworkSlot", "HintStatus"}:

worlds/AutoWorld.py

@@ -295,7 +295,7 @@ class World(metaclass=AutoWorldRegister):
     future. Protocol level compatibility check moved to MultiServer.min_client_version.
     """
 
-    required_server_version: Tuple[int, int, int] = (0, 6, 2)
+    required_server_version: Tuple[int, int, int] = (0, 5, 0)
     """update this if the resulting multidata breaks forward-compatibility of the server"""
 
     hint_blacklist: ClassVar[FrozenSet[str]] = frozenset()