Use a single-stage build for now since Docker Hub doesn't support multi-stage...

Use a single-stage build for now since Docker Hub doesn't support multi-stage builds. Also updated base image to current version of Go, 1.8

Dockerfile

-FROM golang:1.4.1
-RUN mkdir /kube-bench
+FROM golang:1.8
 WORKDIR /kube-bench
+RUN go get github.com/aquasecurity/kube-bench
+RUN cp /go/bin/kube-bench /kube-bench/ && chmod +x /kube-bench/kube-bench
+WORKDIR /kube-bench/cfg
 RUN wget https://raw.githubusercontent.com/aquasecurity/kube-bench/master/cfg/config.yaml && \
     wget https://raw.githubusercontent.com/aquasecurity/kube-bench/master/cfg/federated.yaml && \
     wget https://raw.githubusercontent.com/aquasecurity/kube-bench/master/cfg/master.yaml && \
     wget https://raw.githubusercontent.com/aquasecurity/kube-bench/master/cfg/node.yaml
-RUN go get github.com/aquasecurity/kube-bench
-RUN cp /go/bin/kube-bench /kube-bench/ && chmod +x /kube-bench/kube-bench
-
-FROM alpine:latest
-RUN mkdir -p /kube-bench/cfg
-COPY --from=0 /kube-bench/kube-bench /kube-bench/kube-bench
-COPY --from=0 /kube-bench/config.yaml /kube-bench/cfg/config.yaml
-COPY --from=0 /kube-bench/federated.yaml /kube-bench/cfg/federated.yaml
-COPY --from=0 /kube-bench/master.yaml /kube-bench/cfg/master.yaml
-COPY --from=0 /kube-bench/node.yaml /kube-bench/cfg/node.yaml
+# When Docker Hub supports it, we would split this into a multi-stage build with the second part based on, say, alpine for size
+WORKDIR /
 ADD entrypoint.sh /entrypoint.sh
 ENTRYPOINT /entrypoint.sh