build(deps): update webonyx/graphql-php requirement || ^15.0.0

Updates the requirements on [webonyx/graphql-php](https://github.com/webonyx/graphql-php) to permit the latest version.
- [Release notes](https://github.com/webonyx/graphql-php/releases)
- [Changelog](https://github.com/webonyx/graphql-php/blob/master/CHANGELOG.md)
- [Commits](webonyx/graphql-php@v14.3.0...v15.14.3)

---
updated-dependencies:
- dependency-name: webonyx/graphql-php
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

composer.json

@@ -43,7 +43,7 @@
         "php": "^8.2",
         "amphp/amp": "^2.5",
         "illuminate/support": "^11.0",
-        "webonyx/graphql-php": "^14.3.0"
+        "webonyx/graphql-php": "^14.3.0 || ^15.0.0"
     },
     "require-dev": {
         "graham-campbell/testbench": "^6.0",