Update Maven plugins:

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1164313 13f79535-47bb-0310-9956-ffa450edef68

checkstyle.xml

@@ -31,6 +31,7 @@ limitations under the License.
     <property name="fileExtensions" value="java,xml"/>
   </module>
   <module name="TreeWalker">
+    <property name="cacheFile" value="target/cachefile"/>
     <module name="AvoidStarImport"/>
     <module name="RedundantImport"/>
     <module name="UnusedImports"/>

pom.xml

@@ -512,7 +512,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-changes-plugin</artifactId>
-          <version>2.4</version>
+          <version>2.6</version>
           <configuration>
             <xmlPath>${basedir}/src/site/changes/changes.xml</xmlPath>
             <issueLinkTemplatePerSystem>
@@ -533,7 +533,7 @@
         </plugin>
       <plugin>
         <artifactId>maven-checkstyle-plugin</artifactId>
-        <version>2.6</version>
+        <version>2.7</version>
         <configuration>
           <configLocation>${basedir}/checkstyle.xml</configLocation>
           <enableRulesSummary>false</enableRulesSummary>
@@ -543,7 +543,7 @@
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>findbugs-maven-plugin</artifactId>
-        <version>2.3.1</version>
+        <version>2.3.2</version>
         <configuration>
           <threshold>Normal</threshold>
           <effort>Default</effort>
@@ -553,12 +553,12 @@
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>cobertura-maven-plugin</artifactId>
-        <version>2.4</version>
+        <version>2.5.1</version>
       </plugin>
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>clirr-maven-plugin</artifactId>
-        <version>2.2.2</version>
+        <version>2.3</version>
         <configuration>
           <comparisonArtifacts>
             <comparisonArtifact>
@@ -572,7 +572,7 @@
       </plugin>
       <plugin>
         <artifactId>maven-pmd-plugin</artifactId>
-        <version>2.3</version>
+        <version>2.5</version>
         <configuration>
           <targetJdk>${maven.compile.target}</targetJdk>  
         </configuration>