Use buildpack-deps:stretch-scm instead of the base image for dockerlib

Author: jsternberg

dockerlib/Dockerfile

@@ -4,6 +4,6 @@ RUN set -xe && \
     go get -d github.com/influxdata/influxdata-docker/dockerlib && \
     go install github.com/influxdata/influxdata-docker/dockerlib
 
-FROM debian:stretch
+FROM buildpack-deps:stretch-scm
 COPY --from=builder /go/bin/dockerlib /usr/bin/dockerlib
 ENTRYPOINT ["/usr/bin/dockerlib"]