Read column specifications using readr::spec_csv()

[AndersAskeland]

In the data import section, one could use readr::spec_csv() to investigate the specifications of the data without actually reading it in to memory.

One negative is that vroom does not have this function, which could create some confusion in relation to why they are using vroom.

[lwjohnst86]

Thanks for the issue! I think we should switch strongly consider switching to readr instead of vroom (since vroom is already being used by readr).

[lwjohnst86]

Seems spec_csv() still uses version 1 of readr's code, rather than the updated vroom internal: tidyverse/readr#1387 so keeping this on hold and hopefully they'll update by next year's course.