style: 适配 Java 16 新特性

1.instanceof 模式匹配（Java 14 预览特性 => Java 16 标准特性）
详情请参阅：https://docs.oracle.com/en/java/javase/16/language/pattern-matching-instanceof-operator.html

continew-admin-common/src/main/java/top/charles7c/cnadmin/common/util/ExceptionUtils.java

@@ -44,9 +44,8 @@ public class ExceptionUtils {
      *            异常
      */
     public static void printException(Runnable runnable, Throwable throwable) {
-        if (throwable == null && runnable instanceof Future<?>) {
+        if (throwable == null && runnable instanceof Future<?> future) {
             try {
-                Future<?> future = (Future<?>)runnable;
                 if (future.isDone()) {
                     future.get();
                 }