using notify listener with all-caps channel names

Hello,

I have a project where we set all our notify listeners up using all-caps channel names. In applying your package I found this didn't work, since the add_listener function sends the channel to postgres as a quoted identifier. I monkey patched as such to get it to work for my project:

async def add_listener(self, channel, callback, quote=True):
    """Add a listener for Postgres notifications.

    :param str channel: Channel to listen on.

    :param callable callback:
        A callable receiving the following arguments:
        **connection**: a Connection the callback is registered with;
        **pid**: PID of the Postgres server that sent the notification;
        **channel**: name of the channel the notification was sent to;
        **payload**: the payload.

    :param quote:
        specifies the channel name should should be sent as quoted identifier
    """
    self._check_open()
    if not quote:
        channel = channel.lower()
    if channel not in self._listeners:
        if quote:
            await self.fetch('LISTEN {}'.format(utils._quote_ident(channel)))
        else:
            await self.fetch('LISTEN {}'.format(channel))
        self._listeners[channel] = set()
    self._listeners[channel].add(callback)

Would you consider a pull request with this change? I would think I am not the only one who uses the listeners this way.

Thanks!

Tìm add_listener và utils._quote_ident, sau đó tái hiện hành vi được báo cáo với một kênh thông báo PostgreSQL hoàn toàn viết hoa. Hoàn thành nghĩa là các kênh hoàn toàn viết hoa có thể được đăng ký và nhận thông báo, trong khi hành vi listener hiện có vẫn được giữ nguyên.