Add Follow us on Twitter link to new app screen (#24806)

Summary:
This adds in a link to the reactnative Twitter handle so our users can follow along with the latest and greatest of React Native!

Related to #24760

[General] [Added] - Added link to reactnative Twitter handle to Learn More section
Pull Request resolved: https://github.com/facebook/react-native/pull/24806

Differential Revision: D15316771

Pulled By: cpojer

fbshipit-source-id: cd45f005cfbcbd277fadb48be8943d60f4386767

Libraries/NewAppScreen/components/LearnMoreLinks.js

@@ -54,6 +54,12 @@ const links = [
     description:
       'Need more help? There are many other React Native developers who may have the answer.',
   },
+  {
+    title: 'Follow us on Twitter',
+    link: 'https://twitter.com/reactnative',
+    description:
+      'Stay in touch with the community, join in on Q&As and more by following React Native on Twitter.',
+  },
 ];
 
 const LinkList = () => (