Deprecation notice

[lucasconstantino]

It's my understanding that this library is pretty deprecated and it's main purpose was already implemented into Storybook's core, or was it not? Can we we please add some disclaimer notice on the README and officially archive the repo, if so? As the original creator of is, I'm just trying to ensure my repositories are updated with today's recommendation (or not) of use :)

c.c. @jimmyandrade @ndelangen (by the way: saw you Norbert on React Finland, cool talk 👍)

[ndelangen]

Hey, yeah this is deprecated, and in fact will likely not even work anymore in 7.0. I'll deprecate the repo.