build(deps-dev): bump @types/nodemailer from 6.4.14 to 6.4.15

Bumps [@types/nodemailer](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/nodemailer) from 6.4.14 to 6.4.15.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/nodemailer)

---
updated-dependencies:
- dependency-name: "@types/nodemailer"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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