Bump phpmailer/phpmailer from 6.1.2 to 6.1.3

Bumps [phpmailer/phpmailer](https://github.com/PHPMailer/PHPMailer) from 6.1.2 to 6.1.3.
- [Release notes](https://github.com/PHPMailer/PHPMailer/releases)
- [Changelog](https://github.com/PHPMailer/PHPMailer/blob/master/changelog.md)
- [Commits](PHPMailer/PHPMailer@v6.1.2...v6.1.3)

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

Fixes #26265
PR #1581