Restore missing Optional import in MavenParserTest

Author: timtebeek

rewrite-maven/src/test/java/org/openrewrite/maven/MavenParserTest.java

@@ -43,10 +43,7 @@
 
 import java.net.InetAddress;
 import java.nio.file.Path;
-import java.util.Base64;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
+import java.util.*;
 import java.util.stream.Stream;
 
 import static java.util.stream.Collectors.groupingBy;