Fix Docker dashboard build

Without stripping ownership metadata from the downloaded `grpcurl`
binary we'll end up blowing up at runtine

Author: torkelrogstad

deploy/docker/Dockerfile.dashboard

@@ -31,9 +31,11 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
        esac \
     && curl -fsSL -o /tmp/grpcurl.tgz \
          "https://github.com/fullstorydev/grpcurl/releases/download/v${GRPCURL_VERSION}/grpcurl_${GRPCURL_VERSION}_linux_${GRPCURL_ARCH}.tar.gz" \
-    && tar -xzf /tmp/grpcurl.tgz -C /usr/local/bin grpcurl \
+    && tar -xzf /tmp/grpcurl.tgz --no-same-owner -C /usr/local/bin grpcurl \
     && chmod +x /usr/local/bin/grpcurl \
-    && rm /tmp/grpcurl.tgz
+    && rm /tmp/grpcurl.tgz \
+    # Smoke-test the binary
+    && grpcurl -version
 WORKDIR /app
 COPY --from=deps /app/node_modules ./node_modules
 COPY dashboard/ ./