add optional pullup code

Author: dhalbert

CPB_Keybutton_BLE/code.py

@@ -9,7 +9,7 @@
 """
 import time
 import board
-from digitalio import DigitalInOut, Direction
+from digitalio import DigitalInOut, Direction, Pull
 
 import adafruit_ble
 from adafruit_ble.advertising import Advertisement
@@ -32,6 +32,13 @@
 button_4.direction = Direction.INPUT
 button_5.direction = Direction.INPUT
 
+# NOTE: If you are not using buttons with built-in pullups, uncomment the five lines below.
+# button_1.pull = Pull.UP
+# button_2.pull = Pull.UP
+# button_3.pull = Pull.UP
+# button_4.pull = Pull.UP
+# button_5.pull = Pull.UP
+
 hid = HIDService()
 
 device_info = DeviceInfoService(software_revision=adafruit_ble.__version__,