Bump phpoffice/phpspreadsheet in the composer group

Bumps the composer group with 1 update: [phpoffice/phpspreadsheet](https://github.com/PHPOffice/PhpSpreadsheet).


Updates `phpoffice/phpspreadsheet` from 1.29.4 to 1.29.7
- [Release notes](https://github.com/PHPOffice/PhpSpreadsheet/releases)
- [Changelog](https://github.com/PHPOffice/PhpSpreadsheet/blob/1.29.7/CHANGELOG.md)
- [Commits](PHPOffice/PhpSpreadsheet@1.29.4...1.29.7)

---
updated-dependencies:
- dependency-name: phpoffice/phpspreadsheet
  dependency-type: direct:production
  dependency-group: composer
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]