Upgrade to commons-sandbox-parent-6 pom

git-svn-id: https://svn.apache.org/repos/asf/commons/sandbox/csv/trunk@657403 13f79535-47bb-0310-9956-ffa450edef68

Author: Niall Pemberton

pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>org.apache.commons</groupId>
     <artifactId>commons-sandbox-parent</artifactId>
-    <version>5</version>
+    <version>6</version>
   </parent>
 
   <artifactId>commons-csv</artifactId>