Address issue #26 change number to 'handle'

Author: Brandon Huang

android/src/main/java/io/wazo/callkeep/RNCallKeepModule.java

@@ -524,7 +524,7 @@ public void onReceive(Context context, Intent intent) {
                     sendEventToJS("RNCallKeepDidPerformDTMFAction", args);
                     break;
                 case ACTION_ONGOING_CALL:
-                    args.putString("number", attributeMap.get(EXTRA_CALL_NUMBER));
+                    args.putString("handle", attributeMap.get(EXTRA_CALL_NUMBER));
                     args.putString("callUUID", attributeMap.get(EXTRA_CALL_UUID));
                     args.putString("name", attributeMap.get(EXTRA_CALLER_NAME));
                     sendEventToJS("RNCallKeepDidReceiveStartCallAction", args);