Require @types/protobuf.js at version 5.x as a dependency

Author: jdforsythe

packages/grpc-native-core/package.json

@@ -29,6 +29,7 @@
     "node-pre-gyp"
   ],
   "dependencies": {
+    "@types/protobufjs": "^5.0.31",
     "lodash.camelcase": "^4.3.0",
     "lodash.clone": "^4.5.0",
     "nan": "^2.13.2",