functions in README.md are undefined

[iateadonut]

From going through the tutorial in the README.md, I get these errors:

./main.go:58:21: undefined: smartcar.GetVehicleIDs
./main.go:63:33: smartcarClient.VehicleParams undefined (type smartcar.Client has no field or method VehicleParams)

from my go.mod:

go 1.16

require github.com/smartcar/go-sdk v1.4.0

[iateadonut]

The README.md should read:

vehicleIDs, err := smartcarClient.GetVehicleIDs(
instead of:
vehicleIDs, err := smartcar.GetVehicleIDs(

and
vehicleParams := smartcar.VehicleParams{
instead of:
vehicleParams := smartcarClient.VehicleParams{

Let me know if I should make a PR.