Update graylog2/gelf-php requirement from ^1.6 to ^1.6 || ^2.0

Updates the requirements on [graylog2/gelf-php](https://github.com/bzikarsky/gelf-php) to permit the latest version.
- [Release notes](https://github.com/bzikarsky/gelf-php/releases)
- [Commits](bzikarsky/gelf-php@1.6.0...2.0.1)

---
updated-dependencies:
- dependency-name: graylog2/gelf-php
  dependency-type: direct:production
...

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

composer.json

@@ -10,7 +10,7 @@
         "glesys/butler-auth": "^7.0",
         "glesys/butler-graphql": "^11.0",
         "glesys/butler-health": "^0.6",
-        "graylog2/gelf-php": "^1.6",
+        "graylog2/gelf-php": "^1.6 || ^2.0",
         "guzzlehttp/guzzle": "^7.2",
         "laravel/framework": "^11.0",
         "laravel/octane": "^1.0 || ^2.0",