[maven-release-plugin] prepare release org.apache.felix.dependencymanager-3.1.0

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1437416 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare for next development iteration

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1437418 13f79535-47bb-0310-9956-ffa450edef68