docs: def make_version(ref=None):
      """Build git version string for current directory"""
      cmd = 'git describe --tags --abbrev=6 {}'.format(ref or '')
      with hide('commands'):
          version = local(cmd, capture=True).strip()
      if re.match('^v[0-9]', version):
          version = version[1:]
      # replacements to match semver.org build numbers
      if '-' in version:
          head, _, tail = version.partition('-')
          count, _, sha = tail.partition('-g')
          version = head + '+' + count + '-' + sha
      return version