Add type property to items in payment context

Author: armando-rodriguez-cko

src/CheckoutSdk/Payments/Contexts/PaymentContextItemType.cs

@@ -0,0 +1,13 @@
+using System.Runtime.Serialization;
+
+namespace Checkout.Payments.Contexts
+{
+    public enum PaymentContextItemType
+    {
+        [EnumMember(Value = "physical")]
+        Physical,
+        
+        [EnumMember(Value = "digital")]
+        Digital,
+    }
+}

src/CheckoutSdk/Payments/Contexts/PaymentContextsItems.cs

@@ -2,6 +2,7 @@ namespace Checkout.Payments.Contexts
 {
     public class PaymentContextsItems
     {
+        public PaymentContextItemType? Type { get; set; }
         public string Name { get; set; }
 
         public int Quantity { get; set; }