test_runner: Add parent build ID to request

It will be used to display the URL of the parent build in the UI.

BUG=chromium:1094178
TEST=./generate.sh

Change-Id: I217edb27de568123517c9ec1bda047cda3825d02
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2379232
Tested-by: Alex Zamorzaev <zamorzaev@chromium.org>
Auto-Submit: Alex Zamorzaev <zamorzaev@chromium.org>
Commit-Queue: Prathmesh Prabhu <pprabhu@google.com>
Reviewed-by: Prathmesh Prabhu <pprabhu@google.com>
2 files changed