The setup-node action will default the scope to the correct user (the repo owner), so we do not need to explicitly include it in the workflow. Removing it ensures that the starter template is easier for people to use; now there are no changes necessary to get started. https://github.com/actions/setup-node/blob/master/src/authutil.ts#L26
It was pointed out (https://github.com/actions/labeler/issues/18) that when using the labeler from the starter-workflow, it's not clear that there is more work to do to configure the action. Add information and link to the action's README.
