improve docker build

Signed-off-by: Jonas Franz <info@jonasfranz.software>

Dockerfile

@@ -1,6 +1,9 @@
 #Build stage
 FROM golang:1.10-alpine3.7 AS build-env
 
+
+ARG VERSION
+
 #Build deps
 RUN apk --no-cache add build-base git ca-certificates
 

Dockerfile.web

@@ -1,6 +1,8 @@
 #Build stage
 FROM golang:1.10-alpine3.7 AS build-env
 
+ARG VERSION
+
 #Build deps
 RUN apk --no-cache add build-base git ca-certificates