During the setup process email informations were asked:
- Driver
- Host
- Username
- Password
In some situations the username is not useful because the Cachet's
host may be configured to forward email to a server.
The problem is the username was required, so we had to set a username
and then update the .env file to remove it.
To fix this problem, the mail username has been set to optional in
the setup. So if someone needs a username it still can use this field,
and otherwise people can let it empty.
See: #3244
c9bc2f52d4