fix(docker): include util dir in upstream image build

Include util dir in the upstream image build. Its absence was causing
the build to fail.

Author: njhale

upstream.Dockerfile

@@ -15,6 +15,7 @@ COPY vendor vendor
 COPY go.mod go.mod
 COPY go.sum go.sum
 COPY cmd cmd
+COPY util util
 COPY test test
 RUN make build
 RUN make build-util