Mautrix

* Allowed `postgresql://` scheme in end-to-bridge encryption database URL
(in addition to `postgres://`).
* Slightly improved attr deserialization error messages.

* Changed end-to-bridge encryption to fail if homeserver doesn't advertise
appservice login. This breaks Synapse 1.21, but there have been plenty of
releases since then.
* Switched BaseFileConfig to use the built-in [pkgutil] instead of
pkg_resources (which requires setuptools).
* Added handling for `M_NOT_FOUND` errors when updating `m.direct` account data
through double puppeting in bridges.
* Added logging of data when attr deserializing fails.
* Exposed ExtensibleEnum in `mautrix.types` module.

[pkgutil]: https://docs.python.org/3/library/pkgutil.html

* Changed attr deserializer to deserialize optional missing fields into `None`
instead of `attr.NOTHING` by default.
* Added option not to use transaction for asyncpg database upgrades.

* Added logging when sync errors are resolved.
* Made `.well-known` fetching ignore the response content type header.
* Added handling for users enabling encryption in private chat portals.

* Made SerializableEnum work with int values.
* Added TraceLogger type hints to command handling classes.

* Added logging when sync errors are resolved.
* Made `.well-known` fetching ignore the response content type header.
* Added handling for users enabling encryption in private chat portals.