Use .invalid domain name for InetAddress test

Some DNS setups such as ISP "DNS hijacking" will return an IP address
for garbage names. Using the ".invalid" domain specified in RFC 6761
makes the test more reliable.

src/test/java/picocli/TypeConversionTest.java

@@ -514,7 +514,7 @@ public class TypeConversionTest {
     }
     @Test
     public void testInetAddressConvertersInvalidError() {
-        parseInvalidValue("-InetAddress", "%$::a?*!a", "java.net.UnknownHostException: ");
+        parseInvalidValue("-InetAddress", "test.invalid", "java.net.UnknownHostException: ");
     }
     @Test
     public void testUUIDConvertersInvalidError() {