List project on msgpack.org

If you add msgpack.org[Lua] to the description of this project, their crawler will pick up lua-cmsgpack and add it to the list of implementations on their front page. [See here for details.](https://github.com/msgpack/website/blob/master/README.md#how-to-list-up-your-project-on-msgpackorg)
I was pleased to see a testimonial from the author of this project on their website, and then surprised to see a different Lua implementation in their listing, but not this one.