Update readme

Author: jemmec

README.md

@@ -1,8 +1,18 @@
 # MultiDisplayHoloplay
 
+## Requirements
+
+Tested on Unity version `2021.3.6f1`
+
+Use the latest version of `Holoplay`
+
 ## How to use
 
 - Add a `DisplayManager` to your scene.
-- Add a `DisplayHelper` to the components you want to seperate into different displays.
+- Add a `DisplayHelper` to the components you want to seperate into different displays (UserInterface, Camera, Holoplay).
 - Add the `DisplayHelper` to the `ExternalDisplays` field in the `DisplayManager` and assign the display number you want.
-- Build and run.
+- Build and run.
+
+## Known Issues
+
+- Sometimes the displays are reversed (Holographic display doesn't appear on Looking Glass) just swap the display numbers around in the `DisplayManager` to fix this issue.