Fix for vulnerable dependency path
Fix for vulnerable dependency path

oauthd currently has a 4 vulnerable dependencies, introducing 6 different types of known vulnerabilities.

This PR fixes vulnerable dependency, introducing [remote memory exposure ](https://snyk.io/vuln/npm:request:20160119) vulnerability in the `request` dependency. 

You can see [Snyk test report](https://snyk.io/test/github/oauth-io/oauthd) of this project for details. 

This PR changes `Package.json` to upgrade `request` to the newer 2.74.0 version, and will fix the vulnerability listed above.
You can get alerts and fix PRs for future vulnerabilities for free by [watching this repo with Snyk](https://snyk.io/add).

Note this PR fixes all the vulnerabilities introduced trough `request` dependency, in order to be vulnerability free you will need to upgrade ` prerender-node`, ` restify` and `grunt`, dependencies as well.

Full disclosure: I'm a part of the Snyk team, just looking to spread some security goodness and awareness ;)
pmstss/heroku-oauthd,front/oauthd,dreadjr/oauthd,saltt/oauthd,schaitanya/oauthd,front/oauthd,oauth-io/oauthd,oauth-io/oauthd,front/oauthd,dreadjr/oauthd,dreadjr/oauthd,oauth-io/oauthd,pmstss/heroku-oauthd,pmstss/heroku-oauthd,schaitanya/oauthd,saltt/oauthd,saltt/oauthd,schaitanya/oauthd