Add cvstagdiff into default taskdef list.

PR: 8086
Submitted by: fred@castify.net


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@272431 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/defaults.properties

@@ -67,6 +67,7 @@ dirname=org.apache.tools.ant.taskdefs.Dirname
 cvschangelog=org.apache.tools.ant.taskdefs.cvslib.ChangeLogTask
 buildnumber=org.apache.tools.ant.taskdefs.BuildNumber
 concat=org.apache.tools.ant.taskdefs.Concat
+cvstagdiff=org.apache.tools.ant.taskdefs.cvslib.CvsTagDiff
 
 # optional tasks
 script=org.apache.tools.ant.taskdefs.optional.Script