New - Added variables for each order shipping field
Fix - PHP 7.3 issue where emails were displayed with no CSS
Fix - Possible date rule validation error when using certain comparisons
Fix - Issue where email preview didn't work before the workflow was saved
Tweak - Workflows will now use the customer's email from their account profile in favour of the billing email on their order/subscription. This was changed because it's possible for a user to modify their own email but this doesn't update their orders/subscriptions so it's more logical that they receive emails from the updated email field.
