update plexus (#8)

diff --git a/pom.xml b/pom.xml
index 936711e..281348c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -79,12 +79,12 @@
     <dependency>
       <groupId>org.codehaus.plexus</groupId>
       <artifactId>plexus-utils</artifactId>
-      <version>3.2.0</version>
+      <version>3.3.0</version>
     </dependency>
     <dependency>
       <groupId>org.codehaus.plexus</groupId>
       <artifactId>plexus-interpolation</artifactId>
-      <version>1.25</version>
+      <version>1.26</version>
     </dependency>
     <dependency>
       <groupId>org.sonatype.plexus</groupId>