test_platform: Add Versioning

This will be used for allowing the prod and the dev instances to use
different versions as well as for explicitly specifying the desired
version when creating the build manually.

BUG=chromium:1030538
TEST=./generate.sh

Change-Id: I49420b6ce981756388ebd6592c6b704a880f3c73
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/1967875
Tested-by: Alex Zamorzaev <zamorzaev@chromium.org>
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>
Commit-Queue: Alex Zamorzaev <zamorzaev@chromium.org>
3 files changed