Fix javadoc generation not working with JDK 11

By updating the maven-javadoc-plugin in onos-dependencies.

Change-Id: Ic3085f67ebb0ca341683ef95a6e40c801c38fe93
diff --git a/src/main/java/org/opencord/kafka/integrations/DhcpL2RelayKafkaIntegration.java b/src/main/java/org/opencord/kafka/integrations/DhcpL2RelayKafkaIntegration.java
index f5f1636..58b61b8 100644
--- a/src/main/java/org/opencord/kafka/integrations/DhcpL2RelayKafkaIntegration.java
+++ b/src/main/java/org/opencord/kafka/integrations/DhcpL2RelayKafkaIntegration.java
@@ -52,7 +52,7 @@
             policy = ReferencePolicy.DYNAMIC,
             bind = "bindDhcpL2RelayService",
             unbind = "unbindDhcpL2RelayService")
-    volatile protected DhcpL2RelayService ignore;
+    protected volatile DhcpL2RelayService ignore;
     private final AtomicReference<DhcpL2RelayService> dhcpL2RelayServiceRef = new AtomicReference<>();
 
     private final DhcpL2RelayListener listener = new InternalDhcpL2RelayListener();