fix: drop broken function that should've been removed

hearthstone/cardxml.py

@@ -197,14 +197,6 @@ def max_count_in_deck(self):
 			return 1
 		return 2
 
-	@property
-	def requirements(self):
-		ret = {}
-		for power in self.powers:
-			for reqid, req in power.get("requirements", {}).items():
-				ret[reqid] = req
-		return ret
-
 	@property
 	def quest_reward(self):
 		from .utils import QUEST_REWARDS