Add download instructions to readme

Author: auscompgeek

README.md

@@ -2,4 +2,13 @@
 
 This wraps @ThadHouse's [picocolorsensor][] C++ WPILib side for Python.
 
+Available [on PyPI][] for desktop simulation.
+
+Download for the roboRIO:
+
+```sh
+robotpy-installer download -- --extra-index-url https://m.devpi.net/auscompgeek/rio-2023/+simple picocolorsensor
+```
+
 [picocolorsensor]: https://github.com/ThadHouse/picocolorsensor
+[on PyPI]: https://pypi.org/project/picocolorsensor/