README: Change the status images to SVG

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>

README.md

@@ -5,9 +5,9 @@
  [travis:image]: https://travis-ci.org/keyboardio/Kaleidoscope-EEPROM-Settings.svg?branch=master
  [travis:status]: https://travis-ci.org/keyboardio/Kaleidoscope-EEPROM-Settings
 
- [st:stable]: https://img.shields.io/badge/stable-✔-black.png?style=flat&colorA=44cc11&colorB=494e52
- [st:broken]: https://img.shields.io/badge/broken-X-black.png?style=flat&colorA=e05d44&colorB=494e52
- [st:experimental]: https://img.shields.io/badge/experimental----black.png?style=flat&colorA=dfb317&colorB=494e52
+ [st:stable]: https://img.shields.io/badge/stable-✔-black.svg?style=flat&colorA=44cc11&colorB=494e52
+ [st:broken]: https://img.shields.io/badge/broken-X-black.svg?style=flat&colorA=e05d44&colorB=494e52
+ [st:experimental]: https://img.shields.io/badge/experimental----black.svg?style=flat&colorA=dfb317&colorB=494e52
 
 TODO