Add profile_updated_at to clear cache key (#1795)

app/services/moderator/banisher.rb

@@ -22,7 +22,7 @@ def reassign_and_bust_username
         new_name = "spam_#{rand(10000)}"
         new_username = "spam_#{rand(10000)}"
       end
-      user.update_columns(name: new_name, username: new_username, old_username: user.username)
+      user.update_columns(name: new_name, username: new_username, old_username: user.username, profile_updated_at: Time.current)
       CacheBuster.new.bust("/#{user.old_username}")
     end