Bump laravel/tinker from 2.8.2 to 2.9.0 in /graph-tutorial

Bumps [laravel/tinker](https://github.com/laravel/tinker) from 2.8.2 to 2.9.0.
- [Release notes](https://github.com/laravel/tinker/releases)
- [Changelog](https://github.com/laravel/tinker/blob/2.x/CHANGELOG.md)
- [Commits](laravel/tinker@v2.8.2...v2.9.0)

---
updated-dependencies:
- dependency-name: laravel/tinker
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]