Explicitly use latest golang image

Tobi Fuhrimann · Tobi Fuhrimann · commit 37fd84a56d7c · 2018-05-07T08:56:40.000+02:00
diff --git a/Dockerfile b/Dockerfile
@@ -1,5 +1,5 @@
-FROM golang
+FROM golang:latest
 
-RUN curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh 
+RUN curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
 RUN go get -u github.com/alecthomas/gometalinter && gometalinter --install
 RUN go get -u github.com/frapposelli/wwhrd
