Update symfony/var-dumper requirement from ^6.1 to ^6.1 || ^7.0

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@v6.1.0...v7.1.6)

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

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

composer.json

@@ -25,7 +25,7 @@
         "webmozart/assert": "^1.11"
     },
     "require-dev": {
-        "symfony/var-dumper": "^6.1",
+        "symfony/var-dumper": "^6.1 || ^7.0",
         "php-soap/engine-integration-tests": "^1.5.0",
         "psalm/plugin-symfony": "^5.0",
         "php-standard-library/psalm-plugin": "^2.2",