[6.0] Update learnstorybook tutorial

[dannyhw]

Is your feature request related to a problem? Please describe.

Update the tutorial, talk with @jonniebigodes to coordinate on this.
link to content: https://github.com/bowen9284/learnstorybook.com/tree/master/content/intro-to-storybook/react-native/en

Describe the solution you'd like tutorial works for 6.0

Are you able to assist bring the feature to reality? yes