You need to have commit access to to SONAR-PLUGINS project. If not, just ask for it on dev mailing-list.
- set username/password in settings.xml :
- check that group id is org.codehaus.sonar-plugins, and not org.codehaus.sonar.plugins
- run the maven-release-plugin, use default values :
- update the plugin page in Confluence
- announce the release on Sonar user mailing-list