Bump spatie/laravel-query-builder from 6.3.5 to 6.4.0 in /backend

Bumps [spatie/laravel-query-builder](https://github.com/spatie/laravel-query-builder) from 6.3.5 to 6.4.0.
- [Release notes](https://github.com/spatie/laravel-query-builder/releases)
- [Changelog](https://github.com/spatie/laravel-query-builder/blob/main/CHANGELOG.md)
- [Commits](spatie/laravel-query-builder@6.3.5...6.4.0)

---
updated-dependencies:
- dependency-name: spatie/laravel-query-builder
  dependency-version: 6.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]