update Drupal Commerce source code link (#3710)

- the github mirror does not seem to receive updates since 2020
- ref. #3558

README.md

@@ -836,7 +836,7 @@ _Related: [Community-Supported Agriculture (CSA)](#community-supported-agricultu
 - [Attendize](https://www.attendize.com/) - Ticket selling and event management platform. ([Source Code](https://github.com/attendize/attendize)) `AAL` `Docker/PHP`
 - [Bagisto](https://bagisto.com/en/) - Leading Laravel open source e-commerce framework with multi-inventory sources, taxation, localization, dropshipping and more exciting features. ([Demo](https://demo.bagisto.com/), [Source Code](https://github.com/bagisto/bagisto)) `MIT` `PHP`
 - [CoreShop](https://www.coreshop.org) - CoreShop is a e-commerce plugin for Pimcore. ([Source Code](https://github.com/coreshop/CoreShop)) `GPL-3.0` `PHP`
-- [Drupal Commerce](https://drupalcommerce.org) - Drupal Commerce is a popular e-commerce module for Drupal CMS, with support for dozens of payment, shipping, and shopping related modules. ([Source Code](https://github.com/drupalcommerce/commerce)) `GPL-2.0` `PHP`
+- [Drupal Commerce](https://drupalcommerce.org) - Drupal Commerce is a popular e-commerce module for Drupal CMS, with support for dozens of payment, shipping, and shopping related modules. ([Source Code](https://git.drupalcode.org/project/commerce)) `GPL-2.0` `PHP`
 - [Magento Open Source](https://github.com/magento/magento2) - Leading provider of open omnichannel innovation. `OSL-3.0` `PHP`
 - [Mailchimp Open Commerce](https://mailchimp.com/developer/open-commerce/) - Customizable, real-time reactive, Javascript commerce platform (formerly Reaction Commerce). ([Source Code](https://github.com/reactioncommerce/reaction)) `GPL-3.0` `Nodejs`
 - [MedusaJs](https://medusajs.com/) - Medusa is an open-source headless commerce engine that enables developers to create amazing digital commerce experiences. ([Demo](https://demo.medusajs.com/a/orders?offset=0&limit=15), [Source Code](https://github.com/medusajs/medusa)) `MIT` `Nodejs`