added audible 'beep'

Added audio beep (bell) to make it is easier to interact with the button while the laptop lid is closed

README.md

@@ -13,6 +13,7 @@ Make use of that physical button on the side of  your laptop to run scripts inst
 
 while true; do
 if iwconfig wlp2s0 | grep 'Tx-Power=off' > /dev/null; then
+	echo -e '\a' #beep to indicate interaction
         echo "Wifi is OFF"
 	break
 else