chore(deps): bump github.com/emersion/go-smtp from 0.16.0 to 0.18.1 (#1771)

Bumps [github.com/emersion/go-smtp](https://github.com/emersion/go-smtp) from 0.16.0 to 0.18.1.
- [Release notes](https://github.com/emersion/go-smtp/releases)
- [Commits](https://github.com/emersion/go-smtp/compare/v0.16.0...v0.18.1)

---
updated-dependencies:
- dependency-name: github.com/emersion/go-smtp
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

reporter/email.go

@@ -133,7 +133,7 @@ func (e *emailSender) sendMail(smtpServerAddr, message string) (err error) {
 		return xerrors.Errorf("Failed to send Mail command: %w", err)
 	}
 	for _, to := range emailConf.To {
-		if err = c.Rcpt(to); err != nil {
+		if err = c.Rcpt(to, nil); err != nil {
 			return xerrors.Errorf("Failed to send Rcpt command: %w", err)
 		}
 	}