.arcconfig

py3: work around weird handling of bytes/unicode in decode_header()

Basically decode_header() works as follows, and on Python 3, email headers
ARE UNICODE.

  def decode_header(header):
      if not ecre.search(header):  # ecre is unicode regexp
          return [(header, None)]  # so header is unicode string
      ... decode header into [(bytes_data, unicode_charset_name)]
      return collapsed

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}