Add Makefile for local builds/tests and update gcloud image

Makefile

@@ -0,0 +1,10 @@
+EXECUTABLE := "kubeletmein"
+
+build: clean test
+	go build -ldflags "-extldflags '-static'" -o ${EXECUTABLE} ./cmd/kubeletmein
+
+clean:
+	@rm -f ${EXECUTABLE}
+
+test:
+	go test -v ./pkg/bootstrap

build/Dockerfile

@@ -17,7 +17,7 @@ WORKDIR /out
 RUN curl -sL https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl -o usr/local/bin/kubectl && \
     chmod +x usr/local/bin/kubectl
 
-FROM google/cloud-sdk:239.0.0-alpine
+FROM gcr.io/google.com/cloudsdktool/cloud-sdk:330.0.0-alpine
 LABEL maintainer="Marc Wickenden <marc@4armed.com>"
 
 RUN apk add --no-cache \