Make the PHP test runner conifigurable

PHPUnit, Pest or Paratest.

src/DataTransferObject/ConfigDto.php

@@ -240,6 +240,10 @@ final class ConfigDto
             'phpunit' => new Assert\Optional(
                 new Assert\IsFalse(),
             ),
+
+            'test_runner' => new Assert\Optional(
+                new Assert\Choice(['phpunit', 'pest', 'paratest']),
+            ),
         ],
     )]
     public array $php;