Rails 7: use to_fs(:rfc822) for RSS pubDate (to_s(:format) no longer accepts a format in Rails 7.1+)

app/views/archive_feeds/rssfeed.rss.builder

@@ -8,7 +8,7 @@ xml.rss :version => "2.0" do
       xml.item do
         xml.title archive_file.title
         xml.description archive_file.description
-        xml.pubDate archive_file.created_at.to_s(:rfc822)
+        xml.pubDate archive_file.created_at.to_fs(:rfc822)
         xml.link page_for_archive_file(archive_file, true)
       end
     end