Add mbed_nano and mbed_portenta as supported architectures. (#56)

Author: aentinger

library.properties

@@ -6,5 +6,5 @@ sentence=Arduino Library for network connection management (WiFi, GSM, NB, [Ethe
 paragraph=Originally part of ArduinoIoTCloud
 category=Communication
 url=https://github.com/arduino-libraries/Arduino_ConnectionHandler
-architectures=samd,esp32,esp8266,mbed,megaavr
+architectures=samd,esp32,esp8266,mbed,megaavr,mbed_nano,mbed_portenta
 depends=Arduino_DebugUtils, WiFi101, WiFiNINA, MKRGSM, MKRNB, MKRWAN