Add cool-retro-hyper fun plugin

[fronterior]

Checklist for submitting a resource to awesome-hyper:

• Title: The title for the addition uses its npm title (hyper-example) or the resource's title.
• Link: The link for the addition uses the npmjs.com link (https://www.npmjs.com/package/hyper-example) or the resource's full URI.
• Repository: The package.json file of the resource contains repository information.
• Visual: There is a visual representation of what the addition does in its source repository.
• Location: The awesome addition is in the correct category or sub-category.
  • If it's a plugin or resource, put your awesome item at the BOTTOM of the correct section.
  • If it's a theme, insert it according to the ALPHABETICAL order.
• Description: I've written a short (one sentence) description for the addition in the README.md.
• Downloads: I've added a download stats badge in the second column ([![npm](https://img.shields.io/npm/dm/hyper-example.svg?label=DL)]())

It appears that the repository is no longer managed, but I submit to leave my work.
I didn't know whether to include the category under fun or theme, but the package hyper-postprocessing I referenced is in fun, so I put it under fun.