Add deny option for merchant tokens permission enum to indicate merch…

…ant tokens are not authorised for an operation. (#335)

src/NoFrixion.MoneyMoov/Enums/MerchantTokenPermissionsEnum.cs

@@ -19,6 +19,13 @@ namespace NoFrixion.MoneyMoov;
 [Flags]
 public enum MerchantTokenPermissionsEnum
 {
+    /// <summary>
+    /// Permission to deny all actions. This won't be assigned in practice but when
+    /// checking whether a permission is granted, this can be used to specify that merchant
+    /// tokens are not allowed to perform any actions.
+    /// </summary>
+    Deny = 0,
+
     /// <summary>
     /// Permission to create a payment request
     /// </summary>
@@ -97,5 +104,5 @@ public enum MerchantTokenPermissionsEnum
     /// <summary>
     /// Permission to create and submit a payout from a trusted source.
     /// </summary>
-    TrustedSubmitPayout = 32768
+    TrustedSubmitPayout = 32768,
 }