magento/graphql-ce#387: Test coverage of getting IDs of CMS page/blocks by GraphQL API

1. Set hard dependency

Author: atwixfirster

app/code/Magento/CmsGraphQl/composer.json

@@ -6,6 +6,7 @@
         "php": "~7.1.3||~7.2.0",
         "magento/framework": "*",
         "magento/module-cms": "*",
+        "magento/module-store": "*",
         "magento/module-widget": "*"
     },
     "suggest": {