Add button & LED example for Pimoroni Pico LiPo

micropython/examples/pimoroni_pico_lipo/button_blink.py

@@ -0,0 +1,13 @@
+# This example blinks the user LED on Pimoroni Pico Lipo whilst the BOOT button is pressed.
+# The button is active low, which is why we're using an if not statement!
+
+from machine import Pin
+import time
+
+led = Pin(25, Pin.OUT)
+button = Pin(23, Pin.IN, Pin.PULL_DOWN)
+
+while True:
+    if not button.value():
+        led.toggle()
+        time.sleep(0.5)