Fatal error: Uncaught Error: Class "Doctrine\ORM\Query\ResultSetMapping" not found in D:\xampp\htdocs\pimcore\my-project\vendor\doctrine\orm\src\Query\ResultSetMappingBuilder.php:21 Stack trace: #0 {main} thrown in D:\xampp\htdocs\pimcore\my-project\vendor\doctrine\orm\src\Query\ResultSetMappingBuilder.php on line 21