Update dependencies

ci/install_protobuf.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+set -e
+
+PROTOC_VERSION=$(cat "$(dirname "$(dirname "$0")")/PROTOC_VERSION")
+
+check_protoc_version () {
+  this_version=$(protoc --version)
+  return $([ "libprotoc $PROTOC_VERSION" = "$this_version" ])
+}
+
+if check_protoc_version; then
+    echo "[SUCCESS] protobuf version $PROTOC_VERSION detected."
+    exit
+fi
+
+echo "[INFO] Installing protobuf $PROTOC_VERSION to $HOME/protobuf..."
+
+cd "$TMPDIR"
+wget "https://github.com/protocolbuffers/protobuf/releases/download/v$PROTOC_VERSION/protoc-$PROTOC_VERSION-linux-x86_64.zip"
+unzip -d "$HOME/protobuf" "protoc-$PROTOC_VERSION-linux-x86_64.zip"
+
+echo "[SUCCESS] Done."