add empty measurements file to docker image

Author: metachris

proxy-server.dockerfile

@@ -13,11 +13,13 @@ RUN --mount=type=cache,target=/root/.cache/go-build CGO_ENABLED=0 GOOS=linux \
         -v \
         -o proxy-server \
     cmd/proxy-server/main.go
+RUN echo "{\"azure-tdx\": {}}" > /build/measurements-empty.json
 
 FROM alpine:latest
 WORKDIR /app
 COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
 COPY --from=builder /build/proxy-server /app/proxy-server
+COPY --from=builder /build/measurements-empty.json /app/measurements-empty.json
 ENV LISTEN_ADDR=":8080"
 EXPOSE 8080
 CMD ["/app/proxy-server"]