replace StringBuffer by StringBuilder

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1384337 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/maven/plugin/gpg/AscArtifactMetadata.java b/src/main/java/org/apache/maven/plugin/gpg/AscArtifactMetadata.java
index b348c87..ae179e4 100644
--- a/src/main/java/org/apache/maven/plugin/gpg/AscArtifactMetadata.java
+++ b/src/main/java/org/apache/maven/plugin/gpg/AscArtifactMetadata.java
@@ -57,7 +57,7 @@
 
     private String getFilename()
     {
-        StringBuffer buf = new StringBuffer( 128 );
+        StringBuilder buf = new StringBuilder( 128 );
         buf.append( getArtifactId() );
         buf.append( "-" ).append( artifact.getVersion() );
         if ( isPom )