chore: fix phpstan errors

src/BusProNet/Model/Surcharge.php

@@ -13,7 +13,9 @@ namespace App\BusProNet\Model;
 class Surcharge
 {
     public ?string $label = null;
+    /** @var list<int> */
     public array $mapping = [];
     public ?float $totalPrice = null;
+    /** @var array<int, float|null> */
     public array $individualPrice = [];
 }