Bump PHPUnit

Author: ondrejmirtes

Diff for: composer.json

@@ -34,7 +34,7 @@
 		"php-parallel-lint/php-parallel-lint": "^1.2",
 		"phpstan/phpstan-phpunit": "^1.3.13",
 		"phpstan/phpstan-strict-rules": "^1.5.1",
-		"phpunit/phpunit": "^9.6.16",
+		"phpunit/phpunit": "^9.6.20",
 		"ramsey/uuid": "^4.2",
 		"symfony/cache": "^5.4"
 	},