update readme for Ember Octane

[jelhan]

Updates the readme for Ember Octane. In detail it does:

• Refactor curly bracket component invocation to angle bracket syntax.
• It remove duplicated examples (curly + angle bracket). It's not necessary anymore in my opinion as there isn't anything special about conversion for this addon. It does neither use positional params in curly invocation nor require special arguments for the mapping to HTML attributes.
• Use {{on}} element modifier for event binding instead of {{action}}.
• Uses native classes in the example.
• Use @action decorator instead of actions hash in the examples.

[jelhan]

this binding should be done internally using @action decorator to drop that requirement and simplify to <YourComponent @close={{close}} />. But will leave that one for another PR.

[btecu]

Thanks! Overall looks good. I'll wait until Octane is released before merging.

[jelhan]

@btecu Thanks for your review! Addressed the comments. Do you want me to squash or will you squash it when you merge the PR anyway?

[btecu]

@jelhan I can squash when merging.

[btecu]

Thanks @jelhan!