Fixed GitHub vulnerabilities (#101)

* Fixed GitHub vulnerabilities

Fixed the GitHub vulnerabilities using a yarn upgrade

* Removed node_js version 4 from .travis.yml

* Updated the fuel-auth dependency version in package.json

* Reverted fuel-auth dependency version increase in package.json

Reverted fuel-auth dependency version increase in package.json because since the new auth package was not released, the CI build was failing when trying to fetch it from npm

* fuel-auth version update

.travis.yml

@@ -1,6 +1,5 @@
 language: node_js
 node_js:
-- '4'
 - '6'
 - '8'
 - stable

package.json

@@ -1,6 +1,6 @@
 {
   "name": "fuel-rest",
-  "version": "3.2.1",
+  "version": "3.2.2",
   "description": "Node library for performing REST API calls to Salesforce Marketing Cloud (formerly ExactTarget).",
   "main": "./lib/fuel-rest.js",
   "scripts": {
@@ -32,7 +32,7 @@
     "sinon": "~6.1.3"
   },
   "dependencies": {
-    "fuel-auth": "^3.2.1",
+    "fuel-auth": "^3.3.0",
     "lodash.clone": "~4.5.0",
     "lodash.isplainobject": "~4.0.4",
     "lodash.merge": "^4.6.1",