Fix RFC Error

When using AWS/Mandrill etc, using MAIL_USERNAME as the "From Address"
causes errors. Need to create new .env variable.

.env.example

@@ -15,5 +15,6 @@ MAIL_PORT=587
 MAIL_ENCRYPTION=tls
 MAIL_HOST
 MAIL_USERNAME
+MAIL_FROM_ADDRESS
 MAIL_FROM_NAME
 MAIL_PASSWORD

config/mail.php

@@ -54,7 +54,7 @@ return [
 	|
 	*/
 
-	'from' => ['address' => env('MAIL_USERNAME'), 'name' => env('MAIL_FROM_NAME')],
+	'from' => ['address' => env('MAIL_FROM_ADDRESS'), 'name' => env('MAIL_FROM_NAME')],
 
 	/*
 	|--------------------------------------------------------------------------