Fix execution halt in nrf devices on assert and add --reboot support on nrf (#1397)

* Fix execution halt in nrf devices on assert

* Peg espressif platform to 3.5.0

* Add reboot to nrf52 devices

src/main.cpp

@@ -714,6 +714,8 @@ void powerCommandsCheck()
 #ifndef NO_ESP32
         DEBUG_MSG("Rebooting for update\n");
         ESP.restart();
+#elif NRF52_SERIES
+    NVIC_SystemReset();
 #else
         DEBUG_MSG("FIXME implement reboot for this platform");
 #endif