title: Specify a custom git tag with sbt-release
body: <p>Is it possible to specify a git scheme for git tag names with sbt-release?</p>
  
  <p>The tag commit message and comment can be specified. Per the README:</p>
  
  <p><code>
  releaseTagComment    := s"Releasing ${(version in ThisBuild).value}",
  releaseCommitMessage := s"Setting version to ${(version in ThisBuild).value}",
  </code></p>
  
  <p>But I've been unable to find a way to change the default for the actual tag text, which is set to s"v${releaseVersion}".</p>
  
  <p>I'd like to specify the project name in the tag string, e.g., "myproject-v0.1.1"</p>
  
  <p>To clarify, by the "tag string", I mean the string you see in e.g., <code>git tag -l</code></p>
  
  <p>We have multiple projects in the same git repository, and they have similar version numbers, so tags like "v0.1.0" are ambiguous.</p>