Specify the arch passed as build arg in the distroless image (#848)

Dockerfile

@@ -1,5 +1,6 @@
 # Update the base image in Makefile when updating golang version. This has to
 # be pre-pulled in order to work on GCB.
+ARG ARCH
 FROM golang:1.17.1 as build
 
 RUN apt-get update && apt-get --no-install-recommends install -y libcap2-bin && apt-get clean && rm -rf /var/lib/apt/lists/* 
@@ -19,7 +20,7 @@ ARG GIT_TAG
 RUN make metrics-server
 RUN setcap cap_net_bind_service=+ep metrics-server
 
-FROM gcr.io/distroless/static:latest
+FROM gcr.io/distroless/static:latest-$ARCH
 COPY --from=build /go/src/sigs.k8s.io/metrics-server/metrics-server /
 USER 65534
 ENTRYPOINT ["/metrics-server"]