Mautrix

* *(util.proxy)* Added utility for dynamic proxies (from mautrix-instagram/facebook).
* *(types)* Added default value for `upload_size` in `MediaRepoConfig` as the
field is optional in the spec.
* *(bridge)* Changed ghost invite handling to only process one per room at a time
(thanks to [maltee1] in [132]).

[132]: https://github.com/mautrix/python/pull/132

* *(types)* Changed `set_thread_parent` to inherit the existing thread parent
if a `MessageEvent` is passed, as starting threads from a message in a thread
is not allowed.
* *(util.background_task)* Added new utility for creating background tasks
safely, by ensuring that the task is not garbage collected before finishing
and logging uncaught exceptions immediately.

* *(bridge)* Bumped default timeouts for decrypting incoming messages.

* *(util.async_body)* Added utility for reading aiohttp response into a bytearray
(so that the output is mutable, e.g. for decrypting or encrypting media).
* *(client.api)* Fixed retry loop for MSC3870 URL uploads not exiting properly
after too many errors.

* Marked Python 3.11 as supported. Python 3.8 support will likely be dropped in
the coming months.
* *(client.api)* Added request payload memory optimization to MSC3870 URL uploads.
* aiohttp will duplicate the entire request body if it's raw bytes, which
wastes a lot of memory. The optimization is passing an iterator instead of
raw bytes, so aiohttp won't accidentally duplicate the whole thing.
* The main `HTTPAPI` has had the optimization for a while, but uploading to
URL calls aiohttp manually.

* **Breaking change *(appservice)*** Removed typing status from state store.
* **Breaking change *(appservice)*** Removed `is_typing` parameter from
`IntentAPI.set_typing` to make the signature match `ClientAPI.set_typing`.
`timeout=0` is equivalent to the old `is_typing=False`.
* **Breaking change *(types)*** Removed legacy fields in Beeper MSS events.
* *(bridge)* Removed accidentally nested reply loop when accepting invites as
the bridge bot.
* *(bridge)* Fixed decoding JSON values in config override env vars.