REXML 3.2.8 is not working with rss and test-bundled-gems yet.

https://github.com/ruby/ruby/actions/runs/9125437794/job/25091614796#step:11:272

gems/bundled_gems

@@ -10,7 +10,7 @@ minitest        5.23.0  https://github.com/minitest/minitest
 power_assert    2.0.3   https://github.com/ruby/power_assert 84e85124c5014a139af39161d484156cfe87a9ed
 rake            13.2.1  https://github.com/ruby/rake
 test-unit       3.6.2   https://github.com/test-unit/test-unit
-rexml           3.2.8   https://github.com/ruby/rexml
+rexml           3.2.6   https://github.com/ruby/rexml
 rss             0.3.0   https://github.com/ruby/rss
 net-ftp         0.3.4   https://github.com/ruby/net-ftp
 net-imap        0.4.11  https://github.com/ruby/net-imap