Mautrix

* *(bridge)* Added support for [MSC4190] (thanks to [surakin] in [175]).
* *(appservice)* Renamed `push_ephemeral` in generated registrations to
`receive_ephemeral` to match the accepted version of [MSC2409].

[MSC4190]: https://github.com/matrix-org/matrix-spec-proposals/pull/2781
[surakin]: https://github.com/surakin
[175]: https://github.com/mautrix/python/pull/175

* *(types)* Removed support for generating reply fallbacks to implement
[MSC2781]. Stripping fallbacks is still supported.

[MSC2781]: https://github.com/matrix-org/matrix-spec-proposals/pull/2781

* *(bridge)* Added `/register` call if `/versions` fails with `M_FORBIDDEN`.

**Note:** The `bridge` module is deprecated as all bridges are being rewritten
in Go. See <https://mau.fi/blog/2024-h1-mautrix-updates/> for more info.

* *(client)* Added support for authenticated media downloads.
* *(bridge)* Stopped using cached homeserver URLs for double puppeting if one
is set in the config file.
* *(crypto)* Fixed error when checking OTK counts before uploading new keys.
* *(types)* Added MSC2530 (captions) fields to `MediaMessageEventContent`.

* Dropped Python 3.9 support.
* *(client)* Changed media download methods to log requests and to raise
exceptions on non-successful status codes.

* *(client)* Deprecated MSC2716 methods and added new Beeper-specific batch
send methods, as upstream MSC2716 support has been abandoned.
* *(util.async_db)* Added `PRAGMA synchronous = NORMAL;` to default pragmas.
* *(types)* Fixed `guest_can_join` field name in room directory response
(thanks to [ashfame] in [163]).

[ashfame]: https://github.com/ashfame
[163]: https://github.com/mautrix/python/pull/163