go tidy + missing env variables for build

Dockerfile

@@ -25,15 +25,15 @@ RUN mkdir -p /usr/share/mbrola/
 # setting up builder
 FROM golang:1.15.6-alpine AS builder
 RUN apk add --no-cache git
+
+# compiling the go project
+FROM builder as builder2
 ENV GO111MODULE=on \
     CGO_ENABLED=0 \
     GOOS=linux \
     GOARCH=amd64
 
 WORKDIR /src
-
-# compiling the go project
-FROM builder as builder2
 COPY go.mod go.sum ./
 RUN go mod download
 COPY main.go ./