feat: upgrade phpunit to 12.5

tests/BusProNet/DataLoader/TravelDataLoaderTest.php

@@ -34,7 +34,7 @@ class TravelDataLoaderTest extends TestCase
             ->with('test_file.xml')
             ->willReturn($xmlContent);
 
-        $hotelLoader = $this->createMock(HotelLoader::class);
+        $hotelLoader = $this->createStub(HotelLoader::class);
         $travelParser = $this->createMock(TravelParser::class);
 
         $expectedTravel = new Travel();