Update rexml to version 3.3.9 (#128)

Co-authored-by: depfu[bot] <23717796+depfu[bot]@users.noreply.github.com>

Author: depfu[bot]

Gemfile.lock

@@ -50,7 +50,7 @@ GEM
     rainbow (3.1.1)
     rake (13.0.6)
     regexp_parser (2.8.1)
-    rexml (3.2.6)
+    rexml (3.3.9)
     rspec (3.12.0)
       rspec-core (~> 3.12.0)
       rspec-expectations (~> 3.12.0)