Adds Ecwid by Lightspeed to providers section (#1304)

Co-authored-by: Michael Novotny <[email protected]>

README.md

@@ -27,6 +27,7 @@ Vercel is happy to partner and work with any commerce provider to help them get
 
 - Shopify (this repository)
 - [BigCommerce](https://github.com/bigcommerce/nextjs-commerce) ([Demo](https://next-commerce-v2.vercel.app/))
+- [Ecwid by Lightspeed](https://github.com/Ecwid/ecwid-nextjs-commerce/) ([Demo](https://ecwid-nextjs-commerce.vercel.app/))
 - [Medusa](https://github.com/medusajs/vercel-commerce) ([Demo](https://medusa-nextjs-commerce.vercel.app/))
 - [Saleor](https://github.com/saleor/nextjs-commerce) ([Demo](https://saleor-commerce.vercel.app/))
 - [Shopware](https://github.com/shopwareLabs/vercel-commerce) ([Demo](https://shopware-vercel-commerce-react.vercel.app/))