Can't connect to SMTP server if username lacks '@' symbol
I'm using a free SMTP relay from [SendGrid](https://sendgrid.com/) because DigitalOcean blocks SMTP traffic. When I perform an action in Comentario that should send an email (leaving an anonymous comment for review), I get error 'invalid address "apikey": mail: missing '@' or angle-addr'. Am I configuring something wrong?
secrets.yaml:
```yaml
postgres:
host: localhost
port: 5432
database: comentario
username: comentario
password: ***
smtpServer:
host: smtp.sendgrid.net
username: apikey
password: ***
xsrfSecret: ***
```
SendGrid's API instructions:
Error log:
```
app_1 | 2024-09-18 15:21:59.959 WARNI svc | Failed to send email to nupanick@gmail.com: gomail: could not send email 1: gomail: invalid address "apikey": mail: missing '@' or angle-addr
```
issue