Log Message:
chat/matrix-synapse: Update to 1.48.0

Synapse 1.48.0 (2021-11-30)
===========================

This release removes support for the long-deprecated \ 
`trust_identity_server_for_password_resets` configuration flag.

This release also fixes some performance issues with some background database \ 
updates introduced in Synapse 1.47.0.

Features
--------

- Experimental support for the thread relation defined in \ 
[MSC3440](https://github.com/matrix-org/matrix-doc/pull/3440). \ 
([\#11161](https://github.com/matrix-org/synapse/issues/11161))
- Support filtering by relation senders & types per \ 
[MSC3440](https://github.com/matrix-org/matrix-doc/pull/3440). \ 
([\#11236](https://github.com/matrix-org/synapse/issues/11236))
- Add support for the `/_matrix/client/v3` and `/_matrix/media/v3` APIs from \ 
Matrix v1.1. ([\#11318](https://github.com/matrix-org/synapse/issues/11318), \ 
[\#11371](https://github.com/matrix-org/synapse/issues/11371))
- Support the stable version of \ 
[MSC2778](https://github.com/matrix-org/matrix-doc/pull/2778): the \ 
`m.login.application_service` login type. Contributed by @tulir. \ 
([\#11335](https://github.com/matrix-org/synapse/issues/11335))
- Add a new version of delete room admin API `DELETE \ 
/_synapse/admin/v2/rooms/<room_id>` to run it in the background. \ 
Contributed by @dklimpel. \ 
([\#11223](https://github.com/matrix-org/synapse/issues/11223))
- Allow the admin [Delete Room \ 
API](https://matrix-org.github.io/synapse/latest/admin_api/rooms.html#delete-room-api) \ 
to block a room without the need to join it. \ 
([\#11228](https://github.com/matrix-org/synapse/issues/11228))
- Add an admin API to un-shadow-ban a user. \ 
([\#11347](https://github.com/matrix-org/synapse/issues/11347))
- Add an admin API to run background database schema updates. \ 
([\#11352](https://github.com/matrix-org/synapse/issues/11352))
- Add an admin API for blocking a room. \ 
([\#11324](https://github.com/matrix-org/synapse/issues/11324))
- Update the JWT login type to support custom a `sub` claim. \ 
([\#11361](https://github.com/matrix-org/synapse/issues/11361))
- Store and allow querying of arbitrary event relations. \ 
([\#11391](https://github.com/matrix-org/synapse/issues/11391))

Deprecations and Removals
-------------------------

- Remove deprecated `trust_identity_server_for_password_resets` configuration \ 
flag. ([\#11333](https://github.com/matrix-org/synapse/issues/11333), \ 
[\#11395](https://github.com/matrix-org/synapse/issues/11395))