Update dependency symfony/var-dumper to v6

Signed-off-by: Renovate Bot <bot@renovateapp.com>

| datasource | package            | from  | to    |
| ---------- | ------------------ | ----- | ----- |
| packagist  | symfony/var-dumper | 5.2.0 | 6.0.6 |

composer.json

@@ -26,7 +26,7 @@
         "patchlevel/coding-standard": "^1.0.0",
         "phpstan/phpstan": "^0.12.58",
         "phpunit/phpunit": "^9.4.4",
-        "symfony/var-dumper": "^5.2.0",
+        "symfony/var-dumper": "^6.0.0",
         "vimeo/psalm": "^4.3.1"
     },
     "config": {