Chore(deps-dev): Update guzzlehttp/guzzle requirement

Updates the requirements on [guzzlehttp/guzzle](https://github.com/guzzle/guzzle) to permit the latest version.
- [Release notes](https://github.com/guzzle/guzzle/releases)
- [Changelog](https://github.com/guzzle/guzzle/blob/7.8/CHANGELOG.md)
- [Commits](https://github.com/guzzle/guzzle/compare/7.7.0...7.8.0)

---
updated-dependencies:
- dependency-name: guzzlehttp/guzzle
  dependency-type: direct:development
...

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

tests/integration/composer.json

@@ -2,7 +2,7 @@
     "require-dev": {
         "phpunit/phpunit": "~9",
         "behat/behat": "~3.13.0",
-        "guzzlehttp/guzzle": "7.7.0",
+        "guzzlehttp/guzzle": "7.8.0",
         "jarnaiz/behat-junit-formatter": "^1.3",
         "sabre/dav": "4.4.0",
         "symfony/event-dispatcher": "~5.4"