fix(package): update react-native to version 0.50.1

Closes #34

Author: greenkeeper[bot]

package.json

@@ -15,7 +15,7 @@
   "dependencies": {
     "babel-preset-react-native-stage-0": "1.0.1",
     "react": "16.0.0-alpha.12",
-    "react-native": "0.47.2",
+    "react-native": "0.50.1",
     "react-native-fetch-blob": "0.10.8",
     "react-native-image-resizer": "1.0.0",
     "react-native-modal": "2.5.0",