feature: upgrade react-navigation to v2.

Author: Jekiwijaya

components/yarn.lock

@@ -11,7 +11,7 @@
     "react": "16.0.0",
     "react-native": "0.51.0",
     "react-native-vector-icons": "^4.4.3",
-    "react-navigation": "^1.0.0-beta.22",
+    "react-navigation": "2.0",
     "react-navigation-playground": "0.0.1",
     "utils": "0.0.1"
   },
@@ -20,4 +20,4 @@
     "haul": "^1.0.0-beta.12",
     "react-test-renderer": "16.0.0"
   }
-}
+}