SendWelcomeEmail is not async

[severo]

Maybe it's not very important, but I understand that even if SendWelcomeEmail() is declared as an async function

https://github.com/santiq/bulletproof-nodejs/blob/ee0e80dfba34f7e9b658a4ca4cedf1dd6970511d/src/services/mailer.ts#L10

in reality it's not:

https://github.com/santiq/bulletproof-nodejs/blob/ee0e80dfba34f7e9b658a4ca4cedf1dd6970511d/src/services/mailer.ts#L22-L23

In order to be async, and effectively return only when the email has been set (or in case of error), we would require something like:

return new Promise((resolve, reject) => this.emailClient.messages().send(data, function (error, body) {
  if (error) {
    reject ({ delivered: 0, status: 'error', error });
  } else {
    resolve ({ delivered: 1, status: 'ok' });
  }
});