Bump phpmailer/phpmailer from 5.2.27 to 6.1.6 in /SustProject

Bumps [phpmailer/phpmailer](https://github.com/PHPMailer/PHPMailer) from 5.2.27 to 6.1.6.
- [Release notes](https://github.com/PHPMailer/PHPMailer/releases)
- [Changelog](https://github.com/PHPMailer/PHPMailer/blob/master/changelog.md)
- [Commits](PHPMailer/PHPMailer@v5.2.27...v6.1.6)

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

Author: dependabot[bot]

SustProject/composer.json

@@ -1,7 +1,7 @@
 {
 
   "require": {
-    "phpmailer/phpmailer": "v5.2.27"
+    "phpmailer/phpmailer": "v6.1.6"
   }