code: func (s *Storage) Update(rls *rspb.Release) error {
  	s.Log("updating release %q", makeKey(rls.Name, rls.Version))
  	return s.Driver.Update(makeKey(rls.Name, rls.Version), rls)
  }
docs: // Update update the release in storage. An error is returned if the
  // storage backend fails to update the release or if the release
  // does not exist.