Allow new VAT numbers in Belgium (#21)

* fix: allow new belgium vat numbers

* fix: changed validation message for BE validation

---------

Co-authored-by: Warre Dreesen <[email protected]>

Author: warredr

src/vies-dotnet-api/Validators/BEVatValidator.cs

@@ -19,7 +19,7 @@ limitations under the License.
 namespace Padi.Vies.Validators;
 
 /// <summary>
-/// 
+///
 /// </summary>
 [SuppressMessage("Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses")]
 public sealed class BeVatValidator : VatValidatorAbstract
@@ -34,14 +34,14 @@ public BeVatValidator()
         this.Regex = _regex;
         CountryCode = COUNTRY_CODE;
     }
-        
+
     protected override VatValidationResult OnValidate(string vat)
     {
-        if (vat.Length == 10 && vat[0] != '0')
+        if (vat.Length == 10 && vat[0] != '0' && vat[0] != '1')
         {
-            return VatValidationResult.Failed("First character of 10 digit numbers should be 0.");
+            return VatValidationResult.Failed("First character of 10 digit numbers should be 0 or 1.");
         }
-            
+
         if (vat.Length == 9)
         {
             vat = vat.PadLeft(10, '0');
@@ -54,4 +54,4 @@ protected override VatValidationResult OnValidate(string vat)
             ? VatValidationResult.Failed("Invalid BE vat: checkValue.")
             : VatValidationResult.Success();
     }
-}
+}