Merge commit 'c645490d553124d800d30488595f7d2d9d61584d' into glitch-soc/merge-upstream

Conflicts:
- `Gemfile.lock`:
  Changes were already cherry-picked and updated further in glitch-soc.
  Kept glitch-soc's version.
- `README.md`:
  Upstream updated its README, we have a completely different one.
  Kept glitch-soc's README.
- `app/models/account.rb`:
  Not a real conflict, upstream updated some lines textually adjacent
  to glitch-soc-specific lines.
  Ported upstream's changes.

app/controllers/auth/sessions_controller.rb

@@ -188,7 +188,9 @@ class Auth::SessionsController < Devise::SessionsController
     )
 
     # Only send a notification email every hour at most
-    return if redis.set("2fa_failure_notification:#{user.id}", '1', ex: 1.hour, get: true).present?
+    return if redis.get("2fa_failure_notification:#{user.id}").present?
+
+    redis.set("2fa_failure_notification:#{user.id}", '1', ex: 1.hour)
 
     UserMailer.failed_2fa(user, request.remote_ip, request.user_agent, Time.now.utc).deliver_later!
   end