Dockerfile: optimize incremental build a bit, copy all binaries to output
FROM golang:1.13-alpine AS build-env
WORKDIR /go/src/tailscale
+
+COPY go.mod .
+COPY go.sum .
+RUN go mod download
+
COPY . .
-RUN go get -d -v ./cmd/...
RUN go install -v ./cmd/...
FROM alpine:3.11
RUN apk add --no-cache ca-certificates
-COPY --from=build-env /go/bin/tail* /usr/local/bin/
+COPY --from=build-env /go/bin/* /usr/local/bin/
