Update orchestra/testbench requirement

Updates the requirements on [orchestra/testbench](https://github.com/orchestral/testbench) to permit the latest version.
- [Release notes](https://github.com/orchestral/testbench/releases)
- [Changelog](https://github.com/orchestral/testbench/blob/7.x/CHANGELOG-6.x.md)
- [Commits](https://github.com/orchestral/testbench/commits)

---
updated-dependencies:
- dependency-name: orchestra/testbench
  dependency-type: direct:development
...

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

composer.json

@@ -37,7 +37,7 @@
     "require-dev": {
         "doctrine/dbal": "^3.1",
         "mockery/mockery": "^1.4.4",
-        "orchestra/testbench": "^6.27|^7.0|^6.0",
+        "orchestra/testbench": "^6.27|^7.0|^6.0|^6.0",
         "phpunit/phpunit": "^9.5.8"
     },
     "autoload": {