[maven-release-plugin] prepare release xmlsec-1.5.7

git-svn-id: https://svn.apache.org/repos/asf/santuario/xml-security-java/branches/1.5.x-fixes@1606020 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare for next development iteration

git-svn-id: https://svn.apache.org/repos/asf/santuario/xml-security-java/branches/1.5.x-fixes@1606022 13f79535-47bb-0310-9956-ffa450edef68