fix typetag for pocket trangrams

Author: avivace

entries/pocket-tangrams-vol-1/game.json

@@ -14,5 +14,5 @@
     ],
     "slug": "pocket-tangrams-vol-1",
     "title": "Pocket Tangrams Vol. 1",
-    "typetag": "demo"
-}
+    "typetag": "game"
+}