prototype builder_config.proto: update to match move

This proto was moved in crrev.com/c/2689419.

BUG=None
TEST=./generate.sh

Change-Id: I29b84ad7f6ec9ef92aac2068a74a207a500c18cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2691967
Reviewed-by: George Engelbrecht <engeg@google.com>
Commit-Queue: George Engelbrecht <engeg@google.com>
2 files changed