Add CI files

Author: jissereitsma

.github/workflows/unit-tests.yml

@@ -18,7 +18,7 @@ jobs:
           cp -R $GITHUB_WORKSPACE /tmp/magento/package-source
           cd /tmp/magento
           composer config repositories.local-source path package-source/
-          composer require --prefer-source -- $COMPOSER_NAME:@dev
+          composer require --prefer-source -W -- $COMPOSER_NAME:@dev
 
       - name: Run Magento 2 Unit Tests
         run: |