Set depth to correct 1 (number of commits to fetch)

While it was working ok with zero (0), I verified it in a worker and the checkouts only had the HEAD commit, it's not correct to use depth = 0.

The minimum is 1 and we should be using that number. In fact, both command line and plugin UI setup return an error (fatal: depth 0 is not a positive number) if zero is used. I imagine the pipeline, somehow, automatically applies the 1 and that's the reason it's working.

In any case, better have explicit, correct 1.