I'm not seeing any way to add attachments in the RO workflow Notification block like you can from a Send Email quick action. If you wanted the ease of use functionality there you should log a feature request on the User voice portal.
Beyond that, I'd think you might still be able to accomplish this if you were to somehow attach the desires attachments to a related BO from Service Request, then build a Send Email quick action specific to this template that can grab them with the "Attach from related" dialog. Once that's built you should be able to call that Quick Action from the workflow.
I'm not certain it's possible, but that's the lines I'd think along if I were you.