fix ci dockerfile

tools/Dockerfile.ci

@@ -34,6 +34,13 @@ RUN wget http://nixos.org/releases/patchelf/patchelf-0.10/patchelf-0.10.tar.bz2
     && cd .. \
     && rm -rf patchelf-0.10*
 
+RUN wget https://github.com/protocolbuffers/protobuf/releases/download/v3.11.2/protobuf-all-3.11.2.tar.gz && \
+    tar zxf protobuf-all-3.11.2.tar.gz && \
+    cd protobuf-3.11.2 && \
+    ./configure && make -j4 && make install && \
+    make clean && \
+    cd .. && rm -rf protobuf-*
+
 RUN yum install -y python3 python3-devel
 
 RUN yum -y update >/dev/null \