Update readme.txt (#2507)

Printful integration added to the description

readme.txt

@@ -227,7 +227,8 @@ Never get bored with the old-fashioned appearance of your store. Have full contr
 
 Dokan comes with a number of advanced features & modules that boost your WooCommerce marketplace position, always keeping you one step ahead of the competition. Continuous innovations and features are brought with regular and timely releases. Check out the changelog [here](https://wedevs.com/docs/dokan/changelog/)
 
-* [Stripe Express](https://dokan.co/wordpress/modules/stripe-express/?utm_medium=dokan-lite&utm_source=wordpress.org&utm_campaign=module)(Pro)
+* [Stripe Express](https://dokan.co/wordpress/modules/stripe-express/?utm_medium=dokan-lite&utm_source=wordpress.org&utm_campaign=module)(Pro) 
+* [Print on Demand Marketplace](https://dokan.co/wordpress/modules/printful-integration/?utm_medium=dokan-lite&utm_source=wordpress.org&utm_campaign=module)(Pro)
 * [Minimum Maximum Order](https://dokan.co/wordpress/modules/minimum-maximum-order/?utm_medium=dokan-lite&utm_source=wordpress.org&utm_campaign=modules) (Pro)
 * [Product Advertising](https://dokan.co/wordpress/modules/product-advertising/?utm_medium=dokan-lite&utm_source=wordpress.org&utm_campaign=modules) (Pro)
 * [Product Subscription](https://dokan.co/wordpress/modules/product-subscription/?utm_medium=dokan-lite&utm_source=wordpress.org&utm_campaign=modules) (Pro)