Offset was unexposed in air_get()

[vhorvath]

I came across airtabler, and I think it is a great interface!

I wanted fewer API calls, and quicker turnarounds, I saw that there is air_get() function, but sadly that function did not return offset for pagination, though the documentation at https://rdrr.io/github/bergant/airtabler/man/air_get.html, suggests so.

This is my effort making that function work like documented, and consistent with the behavior of air_select().