dev: sigint-to-sigkill wrapper for gulp
Created by: keegancsmith
gulp doesn't respect C-c. So we add a wrapper to sigkill instead so we don't wait 10s extra to shutdown our dev environment.
Related https://github.com/sourcegraph/sourcegraph/issues/13291 Related https://sourcegraph.slack.com/archives/C07KZF47K/p1604311249138600?thread_ts=1604311249138600&cid=C07KZF47K