feat: upgrade phpunit to 12.5

tests/Controller/Groups/Booking/Step3ControllerTest.php

@@ -156,7 +156,7 @@ class Step3ControllerTest extends TestCase
 
     private function createFormMock(bool $submitted, bool $valid): FormInterface
     {
-        $form = $this->createMock(FormInterface::class);
+        $form = $this->createStub(FormInterface::class);
         $form->method('handleRequest')->willReturnSelf();
         $form->method('isSubmitted')->willReturn($submitted);
         $form->method('isValid')->willReturn($valid);