Marcel Tannich

This plugin will hide the WooCommerce “Update Cart” button and reload the quantity changes dynamic over jQuery. You don’t need this extra click anymore!
This Plugin is based on a posting on StackExchange related to WordPress developers. I modified the basic concept and created a plugin out of it that WordPress users with less experience in PHP can integrate this function easily without destroying their functions.php file.
There are no options. Just activate the plugin and it will works.
<h3>Plugin Requirements</h3>
<ul>
<li>This plugin requires WordPress 4.9 or greater</li>
<li>This plugin requires WooCommerce 3.0.0</li>
<li>This plugin requires PHP 5.6 or greater</li>
</ul>

Dynamic Cart Quantity for WooCommerce

B Hays

Limit the display of product fields with Gravity Forms based on the number of entries.
Currently only works for single product fields with a quantity defined. Limit does not count against entries in the trash.
Great for event registration or product quantity limiting.
Built with Better Inventory with Gravity Forms from Gravity Wiz 
http://gravitywiz.com/better-inventory-with-gravity-forms/

Gravity Forms Quantity Limiter

Limit the display of product fields with Gravity Forms based on the number of entries.

Dynamic Cart Quantity for WooCommerce vs Gravity Forms Quantity Limiter