Added UF2 download instructions in the readme

Author: ksiegall

README.md

@@ -7,6 +7,7 @@
 ### Step 2: Navigate to [xrpcode.wpi.edu](https://xrpcode.wpi.edu)
 
 - Follow instructions there to install MicroPython and the libraries onto the board
+- Please note that this version of the library requires a version of MicroPython specifically for the XRP Control Board. An official download for the firmware is coming soon, but for now, the UF2 file is attached to the most recent release on Github.
 
 ### Step 3: Navigate to the tutorial linked there to learn how to use the bot!