Drop polyfills from examples and README

Author: IvanGoncharov

README.md

@@ -115,7 +115,6 @@ And then use it:
 import * as React from 'react';
 import * as ReactDOM from 'react-dom';
 import { Voyager } from 'graphql-voyager';
-import fetch from 'isomorphic-fetch';
 
 function introspectionProvider(query) {
   return fetch(window.location.origin + '/graphql', {

example/index.html

@@ -14,14 +14,10 @@
     </style>
 
     <!--
-      This GraphQL Voyager example depends on Promise and fetch, which are available in
-      modern browsers, but can be "polyfilled" for older browsers.
       GraphQL Voyager itself depends on React DOM.
       If you do not want to rely on a CDN, you can host these files locally or
       include them directly in your favored resource bunder.
     -->
-    <script src="https://cdn.jsdelivr.net/es6-promise/4.0.5/es6-promise.auto.min.js"></script>
-    <script src="https://cdn.jsdelivr.net/fetch/0.9.0/fetch.min.js"></script>
     <script src="https://cdn.jsdelivr.net/npm/react@16/umd/react.production.min.js"></script>
     <script src="https://cdn.jsdelivr.net/npm/react-dom@16/umd/react-dom.production.min.js"></script>
 

src/middleware/render-voyager-page.ts

@@ -31,7 +31,6 @@ export default function renderVoyagerPage(options: MiddlewareOptions) {
   <link rel="stylesheet"
     href="https://cdn.jsdelivr.net/npm/graphql-voyager@${version}/dist/voyager.css"
   />
-  <script src="https://cdn.jsdelivr.net/fetch/2.0.1/fetch.min.js"></script>
   <script src="https://cdn.jsdelivr.net/npm/react@16/umd/react.production.min.js"></script>
   <script src="https://cdn.jsdelivr.net/npm/react-dom@16/umd/react-dom.production.min.js"></script>
   <script src="https://cdn.jsdelivr.net/npm/graphql-voyager@${version}/dist/voyager.min.js"></script>