Mautrix

* Fixed regression in Python 3.8 support in v0.11.0 due to `asyncio.Queue` type hinting.
* Made the limit of HTTP connections to the homeserver configurable (thanks to justinbot in 64).

* Added support for message send checkpoints (as HTTP requests, similar to the bridge state reporting system) by sumnerevans.
* Added support for aiosqlite with the same interface as asyncpg.
* This includes some minor breaking changes to the asyncpg interface.
* Made config writing atomic (using a tempfile) to prevent the config disappearing when disk is full.
* Changed prometheus to start before rest of `startup_actions` (thanks to Half-Shot in 63).
* Stopped reporting `STARTING` bridge state on startup by sumnerevans.

* Added support for custom bridge bot welcome messages (thanks to justinbot in 58)

* Added support for disabling bridge management commands based on custom rules (thanks to tadzik in 56).

* Changed `remove_room_alias` to ignore `M_NOT_FOUND` errors by default, to preserve Synapse behavior on spec-compliant server implementations. The `raise_404` argument can be set to `True` to not suppress the errors.
* Fixed bridge state pings returning `UNCONFIGURED` as a global state event.

* **Breaking change (serialization):** Removed `Generic[T]` backwards compatibility from `SerializableAttrs` (announced in [v0.9.6](https://github.com/mautrix/python/releases/tag/v0.9.6)).
* Stopped using `self.log` in `Program` config load errors as the logger won't be initialized yet.
* Added check to ensure reply fallback removal is only attempted once.
* Fixed `remove_event_handler` throwing a `KeyError` if no event handlers had been registered for the specified event type.
* Fixed deserialization showing wrong key names on missing key errors.