Bump phpmailer/phpmailer from 6.1.6 to 6.5.0 in /phpmailer

Bump phpmailer/phpmailer from 6.1.6 to 6.5.0 in /phpmailer

Bumps [phpmailer/phpmailer](https://github.com/PHPMailer/PHPMailer) from 6.1.6 to 6.5.0.
- [Release notes](https://github.com/PHPMailer/PHPMailer/releases)
- [Changelog](https://github.com/PHPMailer/PHPMailer/blob/master/changelog.md)
- [Commits](https://github.com/PHPMailer/PHPMailer/compare/v6.1.6...v6.5.0)

---
updated-dependencies:
- dependency-name: phpmailer/phpmailer
  dependency-type: direct:production
...

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