Bump nodemailer from 4.0.1 to 6.9.9

Bumps [nodemailer](https://github.com/nodemailer/nodemailer) from 4.0.1 to 6.9.9.
- [Release notes](https://github.com/nodemailer/nodemailer/releases)
- [Changelog](https://github.com/nodemailer/nodemailer/blob/master/CHANGELOG.md)
- [Commits](https://github.com/nodemailer/nodemailer/compare/v4.0.1...v6.9.9)

---
updated-dependencies:
- dependency-name: nodemailer
  dependency-type: direct:production
...

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

package.json

@@ -74,7 +74,7 @@
     "mongoose-auto-increment": "5.0.1",
     "moox": "^1.0.2",
     "node-schedule": "^1.3.2",
-    "nodemailer": "4.0.1",
+    "nodemailer": "6.9.9",
     "os": "0.1.1",
     "qs": "^6.7.0",
     "react-slick": "^0.17.0",