Implement HTTP Post Action Interface

Author: pykettk

app/code/Magento/Checkout/Controller/Cart/EstimatePost.php

@@ -6,9 +6,10 @@
 namespace Magento\Checkout\Controller\Cart;
 
 use Magento\Framework;
+use Magento\Framework\App\Action\HttpPostActionInterface;
 use Magento\Checkout\Model\Cart as CustomerCart;
 
-class EstimatePost extends \Magento\Checkout\Controller\Cart
+class EstimatePost extends \Magento\Checkout\Controller\Cart implements HttpPostActionInterface
 {
     /**
      * @var \Magento\Quote\Api\CartRepositoryInterface