Convert an organization member to outside collaborator

PUT {{baseUrl}}/orgs/:org/outside_collaborators/:username

When an organization member is converted to an outside collaborator, they'll only have access to the repositories that their current team membership allows. The user will no longer be a member of the organization. For more information, see [Converting an organization member to an outside collaborator](https://help.github.com/articles/converting-an-organization-member-to-an-outside-collaborator/).