wip: finalize implementation

src/BusProNet/Model/BookingResponse.php

@@ -28,6 +28,7 @@ class BookingResponse
         public readonly array $priceItems = [],
         public readonly ?float $totalPrice = null,
         public readonly ?PaymentTerms $paymentTerms = null,
+        public readonly ?string $message = null,
     ) {
     }