This option lets users specify a format of the archive tags. E.g.
  git cl archive -p 'archived/{issue}-{branch}'
makes tags in the format
  archived/1234-foo-feature

Change-Id: Icb74cc68781cda21a70c802bd640543e92ae97a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2116723Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>