avoid/fix obsolete syntax

assignments/src/MV3500Cohort2021JulySeptember/homework3/HittnerDom/HittnerDom3HW.java

@@ -241,7 +241,7 @@ public class HittnerDom3HW
         System.out.println("Network confirmation:" +
                " address=" + disNetworkInterface.getAddress()+ //  disNetworkInterface.getMulticastGroup() + 
                   " port=" + disNetworkInterface.getPort());   // + disNetworkInterface.getDisPort());
-        pduListener = (var newPdu) -> {
+        pduListener = (Pdu newPdu) -> {
             receivedPdu = newPdu;
         } /** Callback handler for listener */ ;
         disNetworkInterface.addListener(pduListener);