fix `DnsResolverTest` license header
diff --git a/pulsar-common/src/test/java/org/apache/pulsar/common/util/netty/DnsResolverTest.java b/pulsar-common/src/test/java/org/apache/pulsar/common/util/netty/DnsResolverTest.java
index 0ccb960..80ab1ea 100644
--- a/pulsar-common/src/test/java/org/apache/pulsar/common/util/netty/DnsResolverTest.java
+++ b/pulsar-common/src/test/java/org/apache/pulsar/common/util/netty/DnsResolverTest.java
@@ -1,4 +1,4 @@
-/*
+/**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information