Bump webonyx/graphql-php from 15.27.2 to 15.28.0

Bumps [webonyx/graphql-php](https://github.com/webonyx/graphql-php) from 15.27.2 to 15.28.0.
- [Release notes](https://github.com/webonyx/graphql-php/releases)
- [Changelog](https://github.com/webonyx/graphql-php/blob/master/CHANGELOG.md)
- [Commits](webonyx/graphql-php@v15.27.2...v15.28.0)

---
updated-dependencies:
- dependency-name: webonyx/graphql-php
  dependency-version: 15.28.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]