bump react-native-android docker image to 2019-5-7

Author: dulmandakh

.circleci/config.yml

@@ -157,7 +157,7 @@ js_defaults: &js_defaults
 android_defaults: &android_defaults
   <<: *defaults
   docker:
-    - image: reactnativecommunity/react-native-android:2019-1-19
+    - image: reactnativecommunity/react-native-android:2019-5-7
   resource_class: "large"
   environment:
     - TERM: "dumb"