code: async function getTagHead(tagName, execaOpts) {
    try {
      return await execa.stdout('git', ['rev-list', '-1', tagName], execaOpts);
    } catch (error) {
      debug(error);
    }
  }
docs: Get the commit sha for a given tag.
  
  @param {String} tagName Tag name for which to retrieve the commit sha.
  @param {Object} [execaOpts] Options to pass to `execa`.
  
  @return {string} The commit sha of the tag in parameter or `null`.