update lodash version

[wyardley]

Can you bump the required lodash version? NSP is warning about vendored dependencies on this and google-gax for https://nodesecurity.io/advisories/577 e.g.,
@google-cloud/pubsub@0.18.0 > google-gax@0.16.1 > grpc@1.8.4 > lodash@4.17.4

[nicolasnoble]

That's not a bad one to change, yes. Feel free to submit a PR to update, and we'll accept it immediately.

[huan]

I have one question: as we are using the TypeScript and ES6, what's the reason that we still need to use lodash to do those jobs?

[nicolasnoble]

@zixia we are absolutely not using TypeScript and ES6 for the grpc-node package.

[huan]

@nicolasnoble You are absolutely right. Sorry for my misunderstanding and thanks for correcting me.