Bump nodemailer from 4.7.0 to 6.9.1

Bumps [nodemailer](https://github.com/nodemailer/nodemailer) from 4.7.0 to 6.9.1.
- [Release notes](https://github.com/nodemailer/nodemailer/releases)
- [Changelog](https://github.com/nodemailer/nodemailer/blob/master/CHANGELOG.md)
- [Commits](nodemailer/nodemailer@v4.7.0...v6.9.1)

---
updated-dependencies:
- dependency-name: nodemailer
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>