chore(deps): bump rexml from 3.3.7 to 3.3.9

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
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -163,7 +163,7 @@ GEM
       rainbow (>= 2.0, < 4.0)
       rexml (~> 3.1)
     regexp_parser (2.9.2)
-    rexml (3.3.7)
+    rexml (3.3.9)
     rouge (4.4.0)
     rspec (3.13.0)
       rspec-core (~> 3.13.0)