code: function tagRelease(done) {
    fs.readFile(config.pkg, 'utf-8', (err, content) => {
      if (err) {
        done(err);
        return;
      }
  
      const pkg = JSON.parse(content);
      const version = pkg.version;
      git.tag(`v${version}`, `release: tag version ${version}`, done);
    });
  }
docs: Tag current version: the tag name will be extracted from
  the `version` field in the `package.json` file.
  
  @param {function} done The `done` callback.
  @return {void}