Please update the APIO documentation.

[zapta]

Please update the APIO documentation at https://upduino.readthedocs.io/en/latest/getting_started/tool_installation.html .

Upduino 3.1 is now supported by the APIO release and the upcoming APIO release will also include two Updiono 3.1 examples that can be created in user space using the apio examples command.

https://github.com/FPGAwars/apio-examples/tree/master/upduino31

I suggest to also add to https://upduino.readthedocs.io/en/latest/getting_started/tool_installation.html a shot explanation on how to install APIO, instantiate the APIO blinky example and build and upload. It should not take more than a few lines of code and will provide a quick start to new Upduino users.