Use Buffer polyfill

Summary: Buffer is not available in the browser

Reviewed By: lblasa

Differential Revision: D44416645

fbshipit-source-id: 9cca069b8b0111f96bb47628e5f2196a22c9812d

desktop/plugins/public/network/utils.tsx

@@ -7,6 +7,7 @@
  * @format
  */
 
+import {Buffer} from 'buffer';
 import decompress from 'brotli/decompress';
 import pako from 'pako';
 import {Request, Header, ResponseInfo} from './types';