Try to fix travis again...

proxy/Dockerfile

@@ -2,5 +2,12 @@ ARG THIS_ARCH_ALT=amd64
 FROM multiarch/alpine:${THIS_ARCH_ALT}-edge
 
 LABEL Lan Tian "lantian@lantian.pub"
-COPY build/proxy /
+ENV GOOS=linux GOARCH=${THIS_ARCH_GO}
+WORKDIR /root
+COPY . .
+RUN apk -q --no-cache add git go build-base upx \
+  && cd /root && go build -o /proxy && upx /proxy \
+  && cd / && rm -rf /root/* \
+  && apk del go build-base upx
+
 ENTRYPOINT ["/proxy"]