Bump phpoffice/phpspreadsheet from 2.2.2 to 3.8.0

Bumps [phpoffice/phpspreadsheet](https://github.com/PHPOffice/PhpSpreadsheet) from 2.2.2 to 3.8.0.
- [Release notes](https://github.com/PHPOffice/PhpSpreadsheet/releases)
- [Changelog](https://github.com/PHPOffice/PhpSpreadsheet/blob/master/CHANGELOG.md)
- [Commits](PHPOffice/PhpSpreadsheet@2.2.2...3.8.0)

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

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

composer.json

@@ -42,7 +42,7 @@
         "nettrine/migrations": "^v0.8",
         "nextras/mail-panel": "^v2.5",
         "php-http/guzzle7-adapter": "^1.0",
-        "phpoffice/phpspreadsheet": "^2.0",
+        "phpoffice/phpspreadsheet": "^3.8",
         "ramsey/uuid": "^4.2",
         "sentry/sentry": "^3.4",
         "skaut/dependent-select-box": "dev-master",