Add a BuilderConfig artifact type for fingerprint MCU unittests

This is a follow-up for http://crrev/c/2422169, which only added
the new artifact type in common.proto. This change adds the same
concept to builder_config.proto

BUG=b:158580909
TEST=generate

Change-Id: Ib5d01a99d3ee4c9b997fdbcca1bc5fa6b15733c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2427552
Commit-Queue: LaMont Jones <lamontjones@chromium.org>
Reviewed-by: LaMont Jones <lamontjones@chromium.org>
2 files changed