fixed mad stalker url

Author: Homebrew Games Website

data/games.json

@@ -157,7 +157,7 @@
         "developer": "Columbus Circle",
         "year": 2020,
         "cover": "assets/games/md/mad-stalker.jpg",
-        "buyUrl": "https://www.romhacking.net/translations/3386/",
+        "buyUrl": "https://www.japanzon.com/en/columbus-circle/6133-columbus-circle-mad-stalker-full-metal-forth-megadrive-4582286323241.html",
         "genre": "Beat 'em Up",
         "tags": [
           "beat-em-up",