chore(deps): bump phpmailer/phpmailer from 6.6.0 to 6.9.1

Bumps [phpmailer/phpmailer](https://github.com/PHPMailer/PHPMailer) from 6.6.0 to 6.9.1.
- [Release notes](https://github.com/PHPMailer/PHPMailer/releases)
- [Changelog](https://github.com/PHPMailer/PHPMailer/blob/master/changelog.md)
- [Commits](PHPMailer/PHPMailer@v6.6.0...v6.9.1)

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

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