Bump phpoffice/phpspreadsheet from 3.4.0 to 3.7.0

Bumps [phpoffice/phpspreadsheet](https://github.com/PHPOffice/PhpSpreadsheet) from 3.4.0 to 3.7.0.
- [Release notes](https://github.com/PHPOffice/PhpSpreadsheet/releases)
- [Changelog](https://github.com/PHPOffice/PhpSpreadsheet/blob/master/CHANGELOG.md)
- [Commits](PHPOffice/PhpSpreadsheet@3.4.0...3.7.0)

---
updated-dependencies:
- dependency-name: phpoffice/phpspreadsheet
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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