Async-upnp-client

- Don't double-unescape action responses (50)
- Add ``UpnpDevice.service_id()`` to get service by service_id. (bazwilliams)
- Fix 'was never awaited'-warning

- Fix timespan formatting for content > 1h
- Try to fix invalid device encodings
- Rename ``async_upnp_client.traffic`` logger to ``async_upnp_client.traffic.upnp`` and add ``async_upnp_client.traffic.ssdp`` logger
- Added ``DeviceUpdater`` to support updating the ``UpnpDevice`` inline on changes to ``BOOTID.UPNP.ORG``/``CONFIGID.UPNP.ORG``/``LOCATION``
- Added support for PAUSED_PLAYBACK state (56, brgerig)
- Add ``DmrDevice.transport_state``, deprecate ``DmrDevice.state``
- Ignore prefix/namespace in DLNA-Events for better compatibility
- DLNA set_transport_uri: Allow supplying own meta_data (e.g. received from a content directory)
- DLNA set_transport_uri: Backwards incompatible change: Only media_uri and media_title are required.
To override mime_type, upnp_class or dlna_features create meta_data via construct_play_media_metadata()

- Added ability to set additional HTTP headers (51)
- Nicer error message on invalid Action Argument
- Store raw received argument value (50)
- Be less strict about didl-lite
- Allow targeted announces (53, elupus)
- Support ipv6 search and advertisements (54, elupus)

- Do not crash on empty XML file (ekandler)
- Option to print timestamp in ISO8601 (kitlaan)
- Option to not print LastChange subscription variable (kitlaan)
- Test with Python 3.8 (scop)
- Less stricter version pinning of ``python-didl-lite`` (fabaff)
- Drop Python 3.5 support, upgrade ``pytest``/``pytest-asyncio``
- Convert type comments to annotations

- Add support for fetching the serialNumber (bdraco)

- Expose ``device_type`` on ``UpnpDevice`` and ``UpnpProfileDevice``