Include mutable property to avoid exception in the latest omnetpp pre…

… version

src/inet/flora/lorabase/LoRaGWMac.ned

@@ -25,7 +25,7 @@ simple LoRaGWMac extends MacProtocolBase like IMacProtocol
 {
     parameters:
         string radioModule = default("^.radio"); // The path to the Radio module  //FIXME remove default value
-        string address = default("auto"); 
+        string address @mutable = default("auto"); 
         string queueModule = default(""); // name of optional external queue module
         int maxQueueSize = default(-1); // maximum queue length in frames; only used if queueModule==""
         bool prioritizeByUP = default(false); // use priority queueing, based on IEEE 802.1d User Priority (UP)