Force nullable type for PHP 8.4 compatibility

Author: jolelievre

.php-cs-fixer.dist.php

@@ -52,6 +52,7 @@
         'single_line_throw' => false,
         'no_alias_language_construct_call' => false,
         'no_null_property_initialization' => false,
+        'nullable_type_declaration_for_default_null_value' => true,
         'global_namespace_import' => [
             'import_classes' => true,
             'import_constants' => false,