Update tone() and remove 3.x support
Updates tone() to work with 4.x and 5.x. Removes support for 3.x.
Thanks to @jepler for the update!
To use in CircuitPython, simply install the Adafruit CircuitPython bundle.
To use in CPython, pip install adafruit-circuitpython-simpleio
.
Read the docs for info on how to use it.