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...v7.1.5)

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

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

composer.json

@@ -48,7 +48,7 @@
 		"phpstan/phpstan-strict-rules": "^1.6",
 		"phpunit/phpunit": "^9.6",
 		"roots/wordpress": "^6.6",
-		"symfony/var-dumper": "^5.4",
+		"symfony/var-dumper": "^7.1",
 		"syntatis/coding-standard": "^1.4",
 		"szepeviktor/phpstan-wordpress": "^1.3",
 		"wp-phpunit/wp-phpunit": "^6.6",