MSHARED-239 update non-crucial plugins to newer versions

I left out modello and plexus-m-p as those somethimes have side effects


git-svn-id: https://svn.apache.org/repos/asf/maven/shared/trunk@1379726 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index 342b5b2..73ff0c9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -109,7 +109,7 @@
     <plugins>
       <plugin>
         <artifactId>maven-javadoc-plugin</artifactId>
-        <version>2.2</version>
+        <version>2.8.1</version>
         <!-- TODO: move configuration to parent POM -->
         <configuration>
           <!-- TODO: not needed under javadoc plugin 2.3, once released -->