message: slightly updated README as in master
diff: [![license](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/ggez/ggez/blob/master/LICENSE)
  [![Crates.io](https://img.shields.io/crates/v/ggez.svg)](https://crates.io/crates/ggez)
  [![Crates.io](https://img.shields.io/crates/d/ggez.svg)](https://crates.io/crates/ggez)
  -![Maintenance](https://img.shields.io/badge/maintenance-passively--maintained-yellowgreen.svg)
  +![Maintenance](https://img.shields.io/badge/maintenance-actively--maintained-green.svg)
  ggez is a Rust library to create a Good Game Easily.
  -The current version is 0.6.0-rc0. This is a RELEASE CANDIDATE version,
  +The current version is 0.6.0-rc1. This is a RELEASE CANDIDATE version,
  which means that the API should be stable but there are still known bugs
  to address. See the release milestone on the issue tracker for details.
  