Update dependencies

Change-Id: I68ef645ae4a54fcc010a0dcecd75a6852ac35bb7
diff --git a/Dockerfile b/Dockerfile
index 7b2d1d1..60c805d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,5 @@
 # Build stage
-FROM golang:latest as build
+FROM golang:latest AS build
 
 RUN apt-get update && \
   apt-get upgrade -y ca-certificates
@@ -7,7 +7,7 @@
 WORKDIR /src
 
 COPY go.mod go.sum ./
-RUN go mod download
+RUN go get -u all
 
 COPY . /src
 
@@ -20,7 +20,7 @@
     --trimpath \
     -o /src/external-big .
 
-FROM gruebel/upx:latest as upx
+FROM gruebel/upx:latest AS upx
 
 COPY --from=build /src/external-big /external-big