Adding an optional --skip-title argument to git cl upload to
automatically use the latest commit message as the patch title, without
requiring the user to hit "enter" to accept.

Change-Id: I0e37b68c809d907a4f980f2be59865e14b1a2db2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2297803Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Mario Bianucci <mabian@microsoft.com>