powerball: fix developer metadata

Author: avivace

entries/rubenretro__powerball/game.json

@@ -20,13 +20,22 @@
             "playable": true
         }
     ],
-    "developer": {
-        "Rubenretro": "https://rubenretro.itch.io",
-        "beatscribe": "https://beatscribe.itch.io",
-        "ainaSGE": "https://ainasge.itch.io"
-    },
+    "developer": [
+        {
+            "name": "Rubenretro",
+            "link": "https://rubenretro.itch.io"
+        },
+        {
+            "name": "beatscribe",
+            "link": "https://beatscribe.itch.io"
+        },
+        {
+            "name": "ainaSGE",
+            "link": "https://ainasge.itch.io"
+        }
+    ],
     "title": "PowerBall: Monster's Quest",
     "date": "2023-09-15",
     "website": "https://rubenretro.itch.io/powerball",
     "slug": "rubenretro__powerball"
-}
+}