Uvicorn-worker

What's Changed
* Bump uvicorn to 0.15.0 by Kludex in https://github.com/Kludex/uvicorn-worker/pull/28
* Drop Python 3.8 by Kludex in https://github.com/Kludex/uvicorn-worker/pull/26

**Full Changelog**: https://github.com/Kludex/uvicorn-worker/compare/0.2.0...0.3.0

This is the first official release of Uvicorn Worker.

It fully matches the implementation of Uvicorn 0.29.0.
The idea is to deprecate the workers within Uvicorn, and point people to this package.