This caused a bit of confusion for a customer who thought that they were
forbidden from passing Path objects in cmd.

R=tandrii@chromium.org

Change-Id: I352a6d5be75f48dcc0c8a8c92d6921359585ed48
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1536493
Commit-Queue: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Auto-Submit: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>