feat(ci): add audit job for security

ci/steps/audit.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+main() {
+  cd "$(dirname "$0")/../.."
+
+  yarn --frozen-lockfile
+
+  yarn _audit
+}
+
+main "$@"