Bugfix invalid DKIM-signature with zero To-addresses
Bugfix invalid DKIM-signature with zero To-addresses

When using PHP's mail() function, and when there are no To-addressees (e.g. only BCC), then the DKIM-signature was not correct. There was a discrepancy between how mail() was called (empty $to) versus the DKIM-signature ('undisclosed-recipients:;').
PHPMailer/PHPMailer,jimjag/PHPMailer,nawawi/PHPMailer,nawawi/PHPMailer,PHPMailer/PHPMailer,jimjag/PHPMailer