[maven-release-plugin] prepare branch maven-shade-plugin-3

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1437375 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] rollback changes from release preparation of maven-shade-plugin-3

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1437377 13f79535-47bb-0310-9956-ffa450edef68