- Add duty_payment option (#318)

Author: nwithan8

EasyPost/Options.cs

@@ -24,6 +24,8 @@ public class Options : Resource
         public string bill_third_party_country { get; set; }
         [JsonProperty("bill_third_party_postal_code")]
         public string bill_third_party_postal_code { get; set; }
+        [JsonProperty("billing_ref")]
+        public string billing_ref { get; set; }
         [JsonProperty("by_drone")]
         public bool? by_drone { get; set; }
         [JsonProperty("carbon_neutral")]
@@ -74,6 +76,8 @@ public class Options : Resource
         public string dry_ice_medical { get; set; }
         [JsonProperty("dry_ice_weight")]
         public string dry_ice_weight { get; set; }
+        [JsonProperty("duty_payment")]
+        public Dictionary<string, object> duty_payment { get; set; }
         [JsonProperty("duty_payment_account")]
         public string duty_payment_account { get; set; }
         [JsonProperty("endorsement")]
@@ -170,8 +174,6 @@ public class Options : Resource
         public string smartpost_hub { get; set; }
         [JsonProperty("smartpost_manifest")]
         public string smartpost_manifest { get; set; }
-        [JsonProperty("billing_ref")]
-        public string billing_ref { get; set; }
         [JsonProperty("special_rates_eligibility")]
         public string special_rates_eligibility { get; set; }
         [JsonProperty("suppress_etd")]