Faker.Vehicle.vin() does not always generate valid VINs

[robacarp]

In US/CA, the final digit of a VIN is a check digit.

Faker currently just picks a random digit and finishes the VIN with that. As a result, about 70% of the time faker generates invalid VINs.

  # Faker does not always generate valid VINs :(
  def vin_factory(_attrs) do
    vin = Faker.Vehicle.vin()

    vin
    |> Vin.valid_vin_string?()
    |> case do
      :ok -> vin
      {:error, _} -> build(:vin)
    end
  end