Add selected repository to an organization secret

Adds a repository to an organization secret when the `visibility` for repository access is set to `selected`. The visibility is set when you [Create or update an organization secret](https://docs.github.com/[email protected]/rest/reference/actions#create-or-update-an-organization-secret). You must authenticate using an access token with the `admin:org` scope to use this endpoint. GitHub Apps must have the `secrets` organization permission to use this endpoint.