Bump nodemailer from 6.9.14 to 6.9.15

Bumps [nodemailer](https://github.com/nodemailer/nodemailer) from 6.9.14 to 6.9.15.
- [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/v6.9.14...v6.9.15)

---
updated-dependencies:
- dependency-name: nodemailer
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

package.json

@@ -23,7 +23,7 @@
     "express": "^4.19.2",
     "joi": "^17.13.3",
     "mongoose": "^8.6.0",
-    "nodemailer": "^6.9.14",
+    "nodemailer": "^6.9.15",
     "speakeasy": "^2.0.0",
     "ts-md5": "^1.3.1"
   },