Update pom.xml

Moving to hadoop 3.1.1

tpch-gen/pom.xml

@@ -19,7 +19,7 @@
     <dependency>
       <groupId>org.apache.hadoop</groupId>
       <artifactId>hadoop-client</artifactId>
-      <version>2.4.0</version>
+      <version>3.1.1</version>
       <scope>compile</scope>
     </dependency>
     <dependency>