better handling of git errors in dbt deps

[drewbanin]

Feature

Feature description

dbt deps can fail for myriad git-related reasons (git isn't installed, the repo can't be cloned, the branch doesn't exist, etc).

dbt currently shows an error like this:

$ dbt deps
Encountered an error:
[Errno 2] No such file or directory: '/var/folders/ql/lb0scpz112lfpcq497_mm3gc0000gn/T/dbt-downloads/18bf9a8e7f78e7bc3bd5414483d4e3f1'

whereas it should instead show the relevant git operation which failed.

The failure is usually visible in the logs, but I got the error above because of a bad spec in packages.yml, which was confusing.

Who will this benefit?

folks who use packages

[beckjake]

Resolved in #1110