Added DefaultSender Postmark setting. Postmark sender addresses must be defined and authorised on the Postmark account, so it's likely a system will use the same sender address for all Postmark emails.
Added DefaultSender Postmark setting. Postmark sender addresses must be defined and authorised on the Postmark account, so it's likely a system will use the same sender address for all Postmark emails.

RhubarbPHP/Module.PostmarkEmail