build(deps): Bump phpmailer/phpmailer from 6.5.4 to 6.6.0 (#256)

Bumps [phpmailer/phpmailer](https://github.com/PHPMailer/PHPMailer) from 6.5.4 to 6.6.0.
- [Release notes](https://github.com/PHPMailer/PHPMailer/releases)
- [Changelog](https://github.com/PHPMailer/PHPMailer/blob/master/changelog.md)
- [Commits](PHPMailer/PHPMailer@v6.5.4...v6.6.0)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>