feat: upgrade phpunit to 12.5

tests/Form/Service/ParticipantVegFieldHandlerTest.php

@@ -204,7 +204,7 @@ class ParticipantVegFieldHandlerTest extends TestCase
 
     private function createMockBookingDto(?Travel $travel = null): BookingDto
     {
-        $bookingDto = $this->createMock(BookingDto::class);
+        $bookingDto = $this->createStub(BookingDto::class);
 
         if (null !== $travel) {
             $bookingDto->travel = $travel;