docs: fix js dependencies in webpack example (#1027)

* docs: fix js dependencies in webpack example

* Update app.js

* Update package.json

* Update package.json

* Update package.json

* Update app.js

Author: dfguo

examples/browser-webpack/package.json

@@ -20,6 +20,6 @@
     "webpack-dev-server": "^2.4.5"
   },
   "dependencies": {
-    "safe-buffer": "^5.0.1"
+    "ipfs": "file:../../"
   }
 }

examples/browser-webpack/src/components/app.js

@@ -1,9 +1,7 @@
 'use strict'
 
 const React = require('react')
-const Buffer = require('safe-buffer').Buffer
-const IPFS = require('../../../../src/core') // replace this by line below
-// const IPFS = require('ipfs')
+const IPFS = require('ipfs')
 
 const stringToUse = 'hello world from webpacked IPFS'