[maven-release-plugin] prepare release maven-jarsigner-1.2

git-svn-id: https://svn.apache.org/repos/asf/maven/shared/trunk@1551773 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@1551776 13f79535-47bb-0310-9956-ffa450edef68