title: Gradle: read latest xy-release GIT tag for versioning
body: <p>I'm currently migrating a project from ant to gradle. Everything is fine, only one problem exists: currently we have a custom ant-contrib based task for executing the git command on the repo to read the latest xy-release tag to get the version number (and version the generated jar filename like project-xy.jar).
  As I can see, I need some plugin for this. Sadly, looking thru the available plugins, nothing really can help me (there exists some git-related plugins, but their goal is something else, like <em>making</em> a release, so tagging the repo, not reading the already-made tags).
  So I need help on reaching my goal. Do I have to invent the whole thing in Gradle? I know I can import existing ant build files, but I don't really want to.</p>