makeybutton: add driver for MakeyMakey-like button

Signed-off-by: deadprogram <ron@hybridgroup.com>

examples/makeybutton/main.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/makeybutton"
+)
+
+var (
+	led    machine.Pin = machine.LED
+	button machine.Pin = machine.BUTTON
+	key    *makeybutton.Button
+)
+
+func main() {
+	led.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	button.Configure(machine.PinConfig{Mode: machine.PinInputPullup})
+	key = makeybutton.NewButton(button)
+
+	for {
+		switch key.Get() {
+		case makeybutton.Pressed:
+			led.High()
+		case makeybutton.Released:
+			led.Low()
+		}
+		time.Sleep(30 * time.Millisecond)
+	}
+}