Issue with constant IDs for a signature required options for domestic shipments

[Lostrishs]

Hi! Found a following issue with constants in your lib:

Regarding the UPS docs, these constants are correct for international shipment:

But, in case I want to set PackageServiceOptions for domestic shipment, I need to use another DSICTypes:

1 is unsupported and 2 is signature required, 3 is adult signature required

It would be great if you will prepare a fix for these constants improve to cover both domestic and international shipments

[szczesuil]

+1 for updating this