build(deps-dev): update symfony/var-dumper requirement from ^5.4 to ^7.1

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@v5.4.0...v7.1.2)

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

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

composer.json

@@ -46,7 +46,7 @@
         "phpstan/phpstan-strict-rules": "^1.3",
         "phpunit/phpunit": "^9.5",
         "symfony/filesystem": "^5.4",
-        "symfony/var-dumper": "^5.4",
+        "symfony/var-dumper": "^7.1",
         "szepeviktor/phpstan-wordpress": "^1.3",
         "vimeo/psalm": "^4.24",
         "yoast/phpunit-polyfills": "^2.0"