User organization
Example
iex> client = %Github.Client{jwt_token: "jwt_token"}
iex> client |> Github.Apps.create_access_token!(12345)
%Github.Client.Response{
body: %{expires_at: "2018-09-04T04:46:29Z", token: "v1.e4f498f111eb59dbcb1bf7148f4dc8c94e7d3372"},
status: 201,
...
}