chore(package): update flow-bin to version 0.68.0 (#49)

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "eslint-plugin-flowtype": "^2.36.0",
     "eslint-plugin-react": "^7.4.0",
     "eslint-plugin-react-native": "^3.1.0",
-    "flow-bin": "^0.67.1",
+    "flow-bin": "^0.68.0",
     "jest": "^22.4.2",
     "istanbul": "^0.4.5",
     "istanbul-api": "1.2.2",