[SDK-2811] Replace request with axios (#144)

* Replace request with got

* Use axios instead of got

* Revert changes

lib/index.js

@@ -3,9 +3,10 @@
  */
 var util = require('util'),
   OAuth2Strategy = require('passport-oauth').OAuth2Strategy,
-  request = require('request'),
+  axios = require('axios'),
   pkg = require('../package.json')
-  crypto = require('crypto');
+  crypto = require('crypto')
+  querystring = require('querystring');
 
 function encodeClientInfo(obj) {
   return Buffer.from(JSON.stringify(obj)).toString('base64');
@@ -159,7 +160,7 @@ Strategy.prototype.authorizationParams = function(options) {
 };
 
 /**
- * TODO: Deprecate
+ * @deprecated An Access Token is already included as part of the verify callback passed to Auth0Strategy.
  */
 Strategy.prototype._getAccessToken = function(done){
   var body = {
@@ -169,23 +170,16 @@ Strategy.prototype._getAccessToken = function(done){
     'grant_type':    'client_credentials'
   };
 
-  request({
+  axios({
     method: 'POST',
     url: this.options.tokenURL,
-    form: body,
-    headers: {
+    data: querystring.stringify(body),
+    headers: { 
       'Auth0-Client': clientInfoHeader
     }
-  }, function (err, resp, body) {
-
-    if(err) return done(err);
-    var result = JSON.parse(body);
-    var accessToken = result['access_token'];
-    var idToken = result['id_token'];
-    done(null, accessToken, idToken);
-  });
-
-
+  })
+    .then((response) => done(null, response.data['access_token'], response.data['id_token']))
+    .catch((err) => done(err));
 };
 
 /**