Update PHP 8 stubs

Author: phpstan-bot

composer.json

@@ -38,7 +38,7 @@
 		"ondrejmirtes/better-reflection": "6.70.0.6",
 		"ondrejmirtes/composer-attribute-collector": "^1.2.0",
 		"ondrejmirtes/php-merge": "^4.1",
-		"phpstan/php-8-stubs": "0.4.38",
+		"phpstan/php-8-stubs": "0.4.39",
 		"phpstan/phpdoc-parser": "2.3.5",
 		"react/child-process": "^0.7",
 		"react/event-loop": "^1.2",