[docs update] 更正浅拷贝的示例

update java-basic-questions-02.md

Author: tiancixiong

docs/java/basis/java-basic-questions-02.md

@@ -123,7 +123,7 @@ public class Student {
 
 ```java
 public class Address implements Cloneable{
-    private final String name;
+    private String name;
     // 省略构造函数、Getter&Setter方法
     @Override
     public Address clone() {