code: public void deleteTag(GitlabProject project, String tagName) throws IOException {
          String tailUrl = GitlabProject.URL + "/" + project + GitlabTag.URL + "/" + tagName;
          retrieve().method(DELETE).to(tailUrl, Void.class);
      }
docs: Delete tag in specific project
  
  @param project
  @param tagName
  @throws IOException on gitlab api call error