Add Selected Repository To An Organization Variable

Adds a repository to an organization variable that is available to selected repositories. Organization variables that are available to selected repositories have their `visibility` field set to `selected`. Authenticated users must have collaborator access to a repository to create, update, or read secrets. OAuth tokens and personal access tokens (classic) need the `admin:org` scope to use this endpoint. If the repository is private, OAuth tokens and personal access tokens (classic) need the...