[maven-release-plugin] prepare for next development iteration

git-svn-id: https://svn.apache.org/repos/asf/maven/pom/trunk@1582496 13f79535-47bb-0310-9956-ffa450edef68
use maven.compiler.source/target standard properties for enforcer bytecode check and pmd

git-svn-id: https://svn.apache.org/repos/asf/maven/pom/trunk@1582500 13f79535-47bb-0310-9956-ffa450edef68