Update symfony/var-dumper requirement from ^6.0.4 to ^7.1.2

Updates the requirements on [symfony/var-dumper](https://github.com/symfony/var-dumper) to permit the latest version.
- [Release notes](https://github.com/symfony/var-dumper/releases)
- [Changelog](https://github.com/symfony/var-dumper/blob/7.1/CHANGELOG.md)
- [Commits](symfony/var-dumper@v6.0.5...v7.1.2)

---
updated-dependencies:
- dependency-name: symfony/var-dumper
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

composer.json

@@ -44,7 +44,7 @@
     "phpunit/phpunit": "^9.6.13|^10.4",
     "povils/phpmnd": "^3.2",
     "roave/security-advisories": "dev-master",
-    "symfony/var-dumper": "^6.0.4"
+    "symfony/var-dumper": "^7.1.2"
   },
   "suggest": {
     "filp/whoops": "Enhance development error reporting (>=2.15)",