Rename README to README.md

Author: keithbradner

README README.mdREADME renamed to README.md

@@ -26,4 +26,4 @@ Documentation can be found online here: [https://valvesoftware.github.io/steamvr
 ### Support
  If you're having trouble with the plugin the best place to discuss issues is our github here: https://github.com/ValveSoftware/steamvr_unity_plugin/issues/
 
- If you'd like to discuss features, post guides, and give general feedback please post on the steam forum here: https://steamcommunity.com/app/250820/discussions/7/
+ If you'd like to discuss features, post guides, and give general feedback please post on the steam forum here: https://steamcommunity.com/app/250820/discussions/7/