Added name() method to identify a button

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[david-fournier-smartnsoft]

I signed it!

[googlebot]

CLAs look good, thanks!

[Fleker]

I'm not sure if knowing the generic name of the GPIO pin is particularly helpful. You may want to keep track of this in your own application using more specific naming for your application. In the RainbowHat driver for example, it abstracts the three buttons to more specific names like openButtonA

[devunwired]

Gpio exposes this attribute, so bubbling it up through the Button seems pretty benign to me. However, I would recommend exposing the actual GPIO value rather than tracking the string independently. Comments added to the code.