Macedonia IBAN parsing rules

Examples

    iex>  %IbanEx.Iban{
    ...>    country_code: "MK",
    ...>    check_digits: "07",
    ...>    bank_code: "250",
    ...>    branch_code: nil,
    ...>    national_check: "84",
    ...>    account_number: "1200000589"
    ...>  }
    ...>  |> IbanEx.Country.MK.to_string()
    "MK 07 250 1200000589 84"