fix: update init banner message with website tagline (#634)

Author: cpojer

packages/cli/src/commands/init/banner.js

@@ -34,7 +34,7 @@ const reactLogoArray = [
 const welcomeMessage =
   '                  Welcome to React Native!                ';
 const learnOnceMessage =
-  '                 Learn Once Write Anywhere                ';
+  '                 Learn once, write anywhere.              ';
 
 export default `${chalk.blue(reactLogoArray.join('\n'))}