Add v3 support for order refunds

WooCommerce/v3/OrderRefund.cs

@@ -1,10 +1,61 @@
 using System;
 using System.Collections.Generic;
 using System.Runtime.Serialization;
+using WooCommerceNET.WooCommerce.v2;
 
 namespace WooCommerceNET.WooCommerce.v3
 {
     [DataContract]
-    public class OrderRefund : v2.OrderRefund { }
-
+    public class OrderRefund : v2.OrderRefund
+    {
+        /// <summary>
+        /// If the payment was refunded via the API.
+        /// read-only
+        /// </summary>
+        [DataMember(EmitDefaultValue = false)]
+        public bool? refunded_payment { get; set; }
+
+        /// <summary>
+        /// Tax lines data. See Order refund - Tax lines properties
+        /// read-only
+        /// </summary>
+        [DataMember(EmitDefaultValue = false)]
+        public List<OrderRefundTaxLine> tax_lines { get; set; }
+
+        /// <summary>
+        /// Shipping lines data. See Order refund - Shipping lines properties
+        /// </summary>
+        [DataMember(EmitDefaultValue = false)]
+        public List<OrderRefundShippingLine> shipping_lines { get; set; }
+
+        /// <summary>
+        /// Fee lines data. See Order refund - Fee lines properties
+        /// </summary>
+        [DataMember(EmitDefaultValue = false)]
+        public List<OrderRefundFeeLine> fee_lines { get; set; }
+
+        /// <summary>
+        /// When true, the selected line items are restocked Default is true.
+        /// write-only
+        /// </summary>
+        [DataMember(EmitDefaultValue = false)]
+        public bool? api_restock { get; set; }
+
+        /// <summary>
+        /// When true, the server computes per-line refund amounts from quantities and validates the request against the order's refund history. Available since WooCommerce 11.1. See Server-computed refunds. Default is false.
+        /// write-only
+        /// </summary>
+        [DataMember(EmitDefaultValue = false)]
+        public bool? compute_totals { get; set; }
+
+    }
+
+    [DataContract]
+    public class OrderRefundTaxLine : OrderTaxLine { }
+
+    [DataContract]
+    public class OrderRefundShippingLine : OrderShippingLine { }
+
+    [DataContract]
+    public class OrderRefundFeeLine : OrderFeeLine { }
 }