Bump commons-io from 2.5 to 2.6

diff --git a/pom.xml b/pom.xml
index 31fa62f..a34bff5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -229,6 +229,11 @@
       <version>3.0.24</version>
     </dependency>
     <dependency>
+      <groupId>commons-io</groupId>
+      <artifactId>commons-io</artifactId>
+      <version>2.6</version>
+    </dependency>
+    <dependency>
       <groupId>org.codehaus.plexus</groupId>
       <artifactId>plexus-interpolation</artifactId>
       <version>1.26</version>