Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `.github/workflows/build-image.yml`:
  Upstream updated `docker/build-push-action`, and we a different config
  for `docker/metadata-action` so the lines directly above were different,
  but it's not a real conflict.
  Upgraded `docker/build-push-action` as upstream did.
- `app/javascript/mastodon/features/compose/components/compose_form.js`:
  Upstream changed the codestyle near a line we had modified to accommodate
  configurable character count.
  Kept our change.

app/lib/feed_manager.rb

@@ -7,7 +7,7 @@ class FeedManager
   include Redisable
 
   # Maximum number of items stored in a single feed
-  MAX_ITEMS = 400
+  MAX_ITEMS = 800
 
   # Number of items in the feed since last reblog of status
   # before the new reblog will be inserted. Must be <= MAX_ITEMS