[Feature Request] Support shoppify emails

[jaredcat]

Add support for shipping emails from Shopify.
They seem to look like they come from: `shop+@t.shopifyemail.com>

Subject lines:
Your <item> Order <order number> is Confirmed! 🎉
Order <order number> confirmed
A shipment from order <order number> is on the way
Shipping update for order <order number>

Note that Shoppify has a PoS and I have an email for a purchase made in-person with the subject
Receipt for order <order number>

Let me know if theres any more information needed