fix: package.json to reduce vulnerabilities
fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/npm:extend:20180424
- https://snyk.io/vuln/npm:hoek:20180212
- https://snyk.io/vuln/npm:stringstream:20180511
- https://snyk.io/vuln/npm:tough-cookie:20170905
- https://snyk.io/vuln/npm:ws:20171108

aarongarvey/binance