reduce steps for jar download

Author: Mehul Batra

website/docs/quickstart/flink-iceberg.md

@@ -36,9 +36,7 @@ cd fluss-quickstart-flink-iceberg
 
 ```shell
 mkdir lib
-cd lib
-wget https://repo1.maven.org/maven2/io/trino/hadoop/hadoop-apache/3.3.5-2/hadoop-apache-3.3.5-2.jar
-cd ..
+wget -O lib/https://repo1.maven.org/maven2/io/trino/hadoop/hadoop-apache/3.3.5-2/hadoop-apache-3.3.5-2.jar
 ```
 
 This jar file provides Hadoop 3.3.5 dependencies required for Iceberg's Hadoop catalog integration.