Bug 480482 - Update maven-clean plugin to 3.0 

Build of swt.binaries has a special cleanup task which is set to use
maven-clean-plugin 2.6.1. Updating it to 3.0.0 strips down the maven2
dependencies being downloaded as this is the first version of the plugin
done as pure maven3 plugin.

Change-Id: I9c4299aafb08e900d3122ac910d9bad482b0a389
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>
diff --git a/pom.xml b/pom.xml
index 5a4c827..fd5cfd3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -75,7 +75,7 @@
     <plugins>
       <plugin>
         <artifactId>maven-clean-plugin</artifactId>
-        <version>2.6.1</version>
+        <version>3.0.0</version>
         <configuration>
           <filesets>
             <fileset>