composer(deps-dev): update orchestra/testbench requirement from ^7.35…

….0 || ^8.0 to ^8.19.0

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/develop/CHANGELOG-8.x.md)
- [Commits](https://github.com/orchestral/testbench/commits/v8.19.0)

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

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

composer.json

@@ -23,7 +23,7 @@
     },
     "require-dev": {
         "ergebnis/composer-normalize": "^2.39",
-        "orchestra/testbench": "^7.35.0 || ^8.0",
+        "orchestra/testbench": "^8.19.0",
         "phpunit/phpunit": "^9.6.0"
     },
     "minimum-stability": "dev",