Add project-agnostic dependency to Golang image

Each project needn't install this dependency during CI setup

golang/latest/Dockerfile

@@ -7,7 +7,7 @@ LABEL version="1.0"
 # Install golint
 ENV GOPATH /go
 ENV PATH ${GOPATH}/bin:$PATH
-RUN go install golang.org/x/lint/golint@latest
+RUN go install golang.org/x/lint/golint@latest && go install github.com/mitchellh/gox@latest
 
 # Install clang
 RUN apt-get update && apt-get install -y --no-install-recommends \