fix link to issues tracker (#466)

Signed-off-by: Olivier Lamy <olamy@apache.org>

Author: olamy

src/site/apt/index.apt.vm

@@ -50,7 +50,7 @@ ${project.name}
   the {{{./mailing-lists.html}mail archive}}.
 
   If you feel like the plugin is missing a feature or has a defect, you can file a feature request or bug report in our
-  {{{https://issues.apache.org/jira/projects/MJAR/issues}issue tracker}}. When creating a new issue, please provide a comprehensive description of your
+  {{{https://github.com/apache/maven-jar-plugin/issues}issue tracker}}. When creating a new issue, please provide a comprehensive description of your
   concern. Especially for fixing bugs it is crucial that the developers can reproduce your problem. For this reason,
   entire debug logs, POMs, or most preferably little demo projects attached to the issue are very much appreciated.
   Of course, patches are welcome, too. Contributors can check out the project from our