modify demo/package.json to fix path

demo/package.json

   "dependencies": {
     "react": "16.0.0-alpha.12",
     "react-native": "0.45.1",
-    "react-native-autoheight-webview": "file:///Users/iou90/Works/Lab/react-native-autoheight-webview"
+    "react-native-autoheight-webview": "../"
   },
   "devDependencies": {
     "babel-jest": "19.0.0",