Use optional property syntax in TCGPlayer interface

src/interfaces/tcgplayer.ts

@@ -2,16 +2,16 @@ export interface TCGPlayer {
   url: string;
   updatedAt: string;
   prices: {
-    normal: Price | undefined;
-    holofoil: Price | undefined;
-    reverseHolofoil: Price | undefined;
+    normal?: Price;
+    holofoil?: Price;
+    reverseHolofoil?: Price;
   }
 }
 
 export interface Price {
-  low: number | null
-  mid: number | null
-  high: number | null
-  market: number | null
-  directLow: number | null
+  low: number | null;
+  mid: number | null;
+  high: number | null;
+  market: number | null;
+  directLow: number | null;
 }