firmware: add FirmwareArtifactInfo proto

Iterating on the metadata.

BUG=b:177907747
TEST=generate

Change-Id: I195725012d801ee610ad0b1796cb158ba9889476
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2685967
Commit-Queue: LaMont Jones <lamontjones@chromium.org>
Commit-Queue: Sean McAllister <smcallis@google.com>
Auto-Submit: LaMont Jones <lamontjones@chromium.org>
Reviewed-by: Sean McAllister <smcallis@google.com>
2 files changed