bb: add -swarming-parent-run-id to 'add' subcommand.
bb: add -swarming-parent-run-id to 'add' subcommand.

R=nodir

Bug: 1004140
Change-Id: If6ee8d0474f53271a4e0f068fc5ec8adfb070061
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/1842778
Auto-Submit: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@google.com>
Commit-Queue: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@google.com>
Reviewed-by: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go