chore: bump webonyx/graphql-php from 15.18.0 to 15.18.1 (#608)

Bumps [webonyx/graphql-php](https://github.com/webonyx/graphql-php) from 15.18.0 to 15.18.1.
- [Release notes](https://github.com/webonyx/graphql-php/releases)
- [Changelog](https://github.com/webonyx/graphql-php/blob/master/CHANGELOG.md)
- [Commits](webonyx/graphql-php@v15.18.0...v15.18.1)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>