[maven-release-plugin] prepare release enforcer-1.3.1

git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1502670 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare for next development iteration

git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1502672 13f79535-47bb-0310-9956-ffa450edef68