Modify the BLE LED Control so that it toggles the LED on the other board only if you keep the button pressed

Revision:
0:8c76e25a3cff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os.lib	Thu Nov 29 18:32:03 2018 +0000
@@ -0,0 +1,1 @@
+https://github.com/ARMmbed/mbed-os/#bf6f2c3c6434a6de9eb9511feffa5948b3d1f20f