update to target nrf52840

Revision:
1:f2e3a692717a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed_coragem.lib	Thu Aug 13 12:56:05 2020 +0000
@@ -0,0 +1,1 @@
+https://github.com/leiachewbacca/mbed_coragem.git/#3ae8d40219ff7dc768c9f2f7c6e64d98ad32d989