Bump rexml from 3.3.7 to 3.3.9 (#2626)

Bumps [rexml](https://github.com/ruby/rexml) from 3.3.7 to 3.3.9.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.3.7...v3.3.9)

---
updated-dependencies:
- dependency-name: rexml
  dependency-type: indirect
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -295,7 +295,7 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
-    rexml (3.3.7)
+    rexml (3.3.9)
     rouge (3.30.0)
     ruby-rc4 (0.1.5)
     rubyzip (2.3.2)