Update form.phtml

Author: nit-it

app/code/Magento/Catalog/view/frontend/templates/product/view/form.phtml

@@ -22,6 +22,7 @@
         <input type="hidden" name="product" value="<?= /* @escapeNotVerified */ $_product->getId() ?>" />
         <input type="hidden" name="selected_configurable_option" value="" />
         <input type="hidden" name="related_product" id="related-products-field" value="" />
+        <input type="hidden" name="item"  value="<?= $block->getRequest()->getParam('id') ?>" />
         <?= $block->getBlockHtml('formkey') ?>
         <?= $block->getChildHtml('form_top') ?>
         <?php if (!$block->hasOptions()):?>