Update guzzlehttp/guzzle requirement from ^6.3 to ^6.3 || ^7.0

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/master/CHANGELOG.md)
- [Commits](guzzle/guzzle@6.3.0...7.3.0)

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

Author: dependabot-preview[bot]

composer.json

@@ -12,7 +12,7 @@
     "require": {
         "php": "^7.3|^8.0",
         "symfony/process": "~3.4 || ~4.0 || ~5.0",
-        "guzzlehttp/guzzle": "^6.3"
+        "guzzlehttp/guzzle": "^6.3 || ^7.0"
     },
     "autoload": {
         "psr-4": {