Mautrix

* *(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

* *(crypto)* Changed `OlmMachine.share_keys` to make the OTK count parameter
optional. When omitted, the count is fetched from the server.
* *(appservice)* Added option to run appservice transaction event handlers
synchronously.
* *(appservice)* Added `log` and `hs_token` parameters to `AppServiceServerMixin`
to allow using it as a standalone class without extending.
* *(api)* Added support for setting appservice `user_id` and `device_id` query
parameters manually without using `AppServiceAPI`.

* *(util.program)* Removed `--base-config` flag in bridges, as there are no
valid use cases (package data should always work) and it's easy to cause
issues by pointing the flag at the wrong file.
* *(bridge)* Added support for the `com.devture.shared_secret_auth` login type
for automatic double puppeting.
* *(bridge)* Dropped support for syncing with double puppets. MSC2409 is now
the only way to receive ephemeral events.
* *(bridge)* Added support for double puppeting with arbitrary `as_token`s.