Move MaxLength of currency to consts file

modules/payment/src/Payment.Application.Contracts/PaymentRequests/PaymentRequestCreationDto.cs

@@ -25,7 +25,7 @@ namespace Payment.PaymentRequests
         /// 3 Letter Language Code in ISO 4217 Standards.
         /// For example: USD, EUR.
         /// </summary>
-        [StringLength(3)]
+        [StringLength(PaymentRequestConsts.MaxCurrencyLength)]
         [CanBeNull]
         public string Currency { get; set; }
     }

modules/payment/src/Payment.Domain.Shared/PaymentRequests/PaymentRequestConsts.cs

@@ -2,6 +2,7 @@
 {
     public static class PaymentRequestConsts
     {
+        public const int MaxCurrencyLength = 100;
         public static int MaxCustomerIdLength { get; set; } = 100;
         public static int MaxProductIdLength { get; set; } = 100;
         public static int MaxProductNameLength { get; set; } = 200;