Bump rexml from 3.3.6 to 3.3.9 (#642)

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>

Author: dependabot[bot]

Gemfile.lock

@@ -123,8 +123,7 @@ GEM
       ffi (~> 1.0)
     redcarpet (3.6.0)
     regexp_parser (2.9.2)
-    rexml (3.3.6)
-      strscan
+    rexml (3.3.9)
     rouge (3.30.0)
     rubocop (1.65.1)
       json (~> 2.3)
@@ -158,7 +157,6 @@ GEM
     standard-performance (1.4.0)
       lint_roller (~> 1.1)
       rubocop-performance (~> 1.21.0)
-    strscan (3.1.0)
     temple (0.10.3)
     thor (1.2.2)
     tilt (2.0.11)