Issue #3249791 by tbradbury: Consider adjustments to shipping amounts.

src/AvataxLib.php

@@ -296,7 +296,7 @@ class AvataxLib implements AvataxLibInterface {
           'taxCode' => $this->config->get('shipping_tax_code'),
           'number' => $shipment->uuid(),
           'description' => $shipment->label(),
-          'amount' => $shipment->getAmount()->getNumber(),
+          'amount' => $shipment->getAdjustedAmount(array_diff($adjustment_types, ['tax']))->getNumber(),
           'quantity' => 1,
           'addresses' => [
             'shipFrom' => self::formatAddress($store->getAddress()),