move commons-io to test scope (#323)

diff --git a/pom.xml b/pom.xml
index f49fed7..845cc78 100644
--- a/pom.xml
+++ b/pom.xml
@@ -197,6 +197,7 @@
       <groupId>commons-io</groupId>
       <artifactId>commons-io</artifactId>
       <version>2.11.0</version>
+      <scope>test</scope>
     </dependency>
 
     <!-- plexus -->