WHSIKER-12 Problems with MOJO on CI

- Upgrading maven-plugin-stuff in order to hopefully get a green build on CI.
- Added mojo-attribute that no project is required to run this plugin.



git-svn-id: https://svn.apache.org/repos/asf/creadur/whisker/trunk@1619921 13f79535-47bb-0310-9956-ffa450edef68