Pre-fill customer email on CoinGate Invoice from WooCommerce Order

[brnbs]

According to the CoinGate API, it is possible to send the billing address from WooCommerce to the CoinGate Payment page, see purchaser_email field on the Create Order method:

So please modify the $params array at this location to include purchaser_email field:

'description'      => implode( ', ', $description ),
'purchaser_email'   => $order->get_billing_email(),

This makes the checkout process easier for customers because they don't have to enter their email address twice.