Update PriceMessage.cs

Author: KoesterRobert

Source/FikaAmazonAPI/ConstructFeed/Messages/PriceMessage.cs

@@ -7,5 +7,8 @@ public class PriceMessage
         public StandardPrice StandardPrice { get; set; }
 
         public Sale Sale { get; set; }
+        public decimal BusinessPrice { get; set; }
+        public StandardPrice MinimumSellerAllowedPrice { get; set; }
+        public StandardPrice MaximumSellerAllowedPrice { get; set; }
     }
 }