Add upgrade notes for new quarantined_media_changes stream (#19694)

Fixes https://github.com/element-hq/synapse/issues/19692

Introduced by https://github.com/element-hq/synapse/pull/19558

---------

Co-authored-by: Eric Eastwood <madlittlemods@gmail.com>

changelog.d/19694.feature

@@ -0,0 +1 @@
+Add a ["Listing quarantined media changes" Admin API](https://element-hq.github.io/synapse/latest/admin_api/media_admin_api.html#listing-quarantined-media-changes) for retrieving a paginated record of when media became (un)quarantined.

docs/upgrade.md

@@ -117,6 +117,19 @@ each upgrade are complete before moving on to the next upgrade, to avoid
 stacking them up. You can monitor the currently running background updates with
 [the Admin API](usage/administration/admin_api/background_updates.html#status).
 
+# Upgrading to v1.152.0
+
+## Workers which quarantine media must be stream writers
+
+A new [`quarantined_media_changes` stream writer](./workers.md#the-quarantined_media_changes-stream) is
+introduced. Existing deployments which route the `/quarantine_media` endpoints to a
+worker (instead of the main process) *must* also add those workers to the
+`quarantined_media_changes` stream writer list. Quarantining media will not work without
+this.
+
+If your deployment does not use workers, or instead uses the main process for
+quarantining media, you do not need to make any changes to your configuration.
+
 # Upgrading to v1.150.0
 
 ## Removal of the `systemd` pip extra