chore(deps): Bump nodemailer from 6.7.0 to 6.9.9

Bumps [nodemailer](https://github.com/nodemailer/nodemailer) from 6.7.0 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/v6.7.0...v6.9.9)

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

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

packages/backend/package.json

@@ -57,7 +57,7 @@
     "morgan": "^1.10.0",
     "multer": "1.4.5-lts.1",
     "node-html-markdown": "^1.3.0",
-    "nodemailer": "6.7.0",
+    "nodemailer": "6.9.9",
     "oauth-1.0a": "^2.2.6",
     "objection": "^3.0.0",
     "passport": "^0.6.0",