Remove browser support

Author: ThisIsMissEm

browser.js

@@ -3,13 +3,11 @@
   "version": "2.2.0",
   "description": "A light-weight module that brings window.fetch to node.js",
   "main": "lib/index",
-  "browser": "./browser.js",
   "module": "lib/index.mjs",
   "files": [
     "lib/index.js",
     "lib/index.mjs",
-    "lib/index.es.js",
-    "browser.js"
+    "lib/index.es.js"
   ],
   "engines": {
     "node": "4.x || >=6.0.0"