Update Go language version 1.6.3 -> 1.9.0, as well as Alpine 3.4 -> 3.6 (#81)

* Update Go language version 1.6.3 -> 1.9.0, as well as Alpine 3.4 -> 3.6

Author: ohaiwalt

Dockerfile

@@ -1,17 +1,14 @@
-FROM alpine:3.4
+FROM golang:1.9.0-alpine3.6
 
 MAINTAINER Christopher Maier <christopher.maier@gmail.com>
 
-ENV GO_PACKAGE_VERSION 1.6.3-r0
 ENV GOPATH /gopath
 ENV PATH=${GOPATH}/bin:${PATH}
 
 WORKDIR /gopath/src/github.com/operable/go-relay
 COPY . /gopath/src/github.com/operable/go-relay
 
 RUN apk -U add --virtual .build_deps \
-    go=$GO_PACKAGE_VERSION \
-    go-tools=$GO_PACKAGE_VERSION \
     git make && \
 
     go get -u github.com/kardianos/govendor && \