Add guide_version for the mftf/v2 scope

Author: dshevtsov

_config.yml

@@ -96,6 +96,7 @@ defaults:
     scope:
       path: mftf/v2
     values:
+      guide_version: 2.3
       group: mftf-v2
       github_files: https://github.com/magento/magento2-functional-testing-framework/tree/2.6.5/
       github_repo: https://github.com/magento/magento2-functional-testing-framework/