Add MyPluginPostStatusInfo example

[Soean]

Adds an example for MyPluginPostStatusInfo to replace post submitbox actions.
Fixes #13

Should we add ES5 or ES6/JSX examples or both?

[danielbachhuber]

Thanks!

Should we add ES5 or ES6/JSX examples or both?

This ES6 example seems fine. Do you want to extend the example to be UI that saves data to the database?

[Soean]

@danielbachhuber Something like this? https://github.com/inpsyde/gutenberg-example/blob/master/assets/js/src/EditorPicks/index.js

[danielbachhuber]

Something like this? https://github.com/inpsyde/gutenberg-example/blob/master/assets/js/src/EditorPicks/index.js

Yep, that'd work. We can link to it instead of duplicating.