Consider cross-fetch

latest 'node-fetch' throws type errors consider https://www.npmjs.com/package/cross-fetch 

```
import fetch from 'cross-fetch'
import { JsonRpc } from 'eosjs'

// Instantiate a new JsonRpc object, with the Network Api Uri, and a request object
const rpc = new JsonRpc('https://api.kylin.alohaeos.com', { fetch })
```