The “Allow local actions only” option in the Organization settings means that the actions (don’t confuse with workflows) only defined in the repositories within current organization can be used in the workflows within current organization. The workflows within current organization can’t use the actions defined outside of current organization.
That’s why you get the message:
actions/checkout@v2 and actions/setup-node@v2-beta are not allowed to be used in Upvision/upvision.github.io. Actions in this workflow must be: within a repository owned by Upvision.
Because the “checkout” action and “setup-node” action are defined within the “actions” organization, not your organization “Upvision”.
If you want to use the actions from other organizations, you can:
select “Allow all actions”, the actions from anywhere can be used in the workflows within current organization.
select “Allow select actions”, specify the actions you want to run within current organization. The specified actions can be from anywhere.
About workflows from fork repository, there also are some option you can use in the Organization settings.
To view more details, you can see “Disabling or limiting GitHub Actions for your organization”.