[Java] Upgrade checkstyle plugin (#4375)

java/api/src/main/java/org/ray/api/RayActor.java

@@ -4,6 +4,7 @@ import org.ray.api.id.UniqueId;
 
 /**
  * A handle to an actor.
+ *
  * @param <T> The type of the concrete actor class.
  */
 public interface RayActor<T> {

java/api/src/main/java/org/ray/api/WaitResult.java

@@ -1,6 +1,5 @@
 package org.ray.api;
 
-
 import java.util.List;
 
 /**