chore: Bump rexml from 3.3.6 to 3.3.9 (#2231)

Bumps [rexml](https://github.com/ruby/rexml) from 3.3.6 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@v3.3.6...v3.3.9)

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

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

Gemfile.lock

@@ -637,8 +637,7 @@ GEM
       railties (>= 5.2)
     reverse_markdown (2.1.1)
       nokogiri
-    rexml (3.3.6)
-      strscan
+    rexml (3.3.9)
     rmagick (5.5.0)
       observer (~> 0.1)
       pkg-config (~> 1.4)
@@ -783,7 +782,6 @@ GEM
       activesupport (>= 6.1)
       sprockets (>= 3.0.0)
     stackprof (0.2.26)
-    strscan (3.1.0)
     swd (2.0.3)
       activesupport (>= 3)
       attr_required (>= 0.0.5)