Bump nodemailer from 3.1.8 to 6.6.1

Bumps [nodemailer](https://github.com/nodemailer/nodemailer) from 3.1.8 to 6.6.1.
- [Release notes](https://github.com/nodemailer/nodemailer/releases)
- [Changelog](https://github.com/nodemailer/nodemailer/blob/master/CHANGELOG.md)
- [Commits](nodemailer/nodemailer@v3.1.8...v6.6.1)

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

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

Author: dependabot[bot]