(deps): move the window.resizeTo polyfill to its own package

- and import & use it here!

Author: agilgur5

jest.config.js

@@ -5,7 +5,7 @@ module.exports = {
     // configure enzyme w/ react adapter
     '<rootDir>/test/config/configure-enzyme.js',
     // polyfill window.resizeTo
-    '<rootDir>/test/config/window-resizeTo.js'
+    'window-resizeto/polyfill'
   ],
   transform: {
     // use babel-jest@23 for babel@6 support (https://github.com/facebook/jest/issues/8230#issuecomment-479470547)

package-lock.json

@@ -75,6 +75,7 @@
     "standard": "^13.0.2",
     "style-loader": "^0.13.1",
     "webpack": "^1.12.2",
-    "webpack-dev-server": "^1.10.1"
+    "webpack-dev-server": "^1.10.1",
+    "window-resizeto": "0.0.2"
   }
 }