[maven-release-plugin] prepare release maven-shared-utils-0.6

git-svn-id: https://svn.apache.org/repos/asf/maven/shared/trunk@1578828 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare for next development iteration

git-svn-id: https://svn.apache.org/repos/asf/maven/shared/trunk@1578830 13f79535-47bb-0310-9956-ffa450edef68