title: Tag a remote git repository without cloning it
body: <p>Is there a way to tag a remote git repository <em>without having cloned it</em> locally?</p>
  
  <p>In order to correlate a code repository with a config repository, I want to (as a CI build step) tag whatever is the current head of the config repository with build-n (where N is the current build number provided by jenkins).</p>
  
  <p>The config repository isn't used as part of the build, I simply want an easy way to fetch the config revision as it was when for example version 1234 was built, and tagging it as "build-1234" seems like the simplest way to achieve this.</p>