Bump rexml from 3.3.6 to 3.3.9 (#28)

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

@@ -8,8 +8,7 @@ GEM
       ast (~> 2.4.1)
     rainbow (3.1.1)
     regexp_parser (2.8.0)
-    rexml (3.3.6)
-      strscan
+    rexml (3.3.9)
     rubocop (1.51.0)
       json (~> 2.3)
       parallel (~> 1.10)
@@ -23,7 +22,6 @@ GEM
     rubocop-ast (1.28.1)
       parser (>= 3.2.1.0)
     ruby-progressbar (1.13.0)
-    strscan (3.1.0)
     unicode-display_width (2.4.2)
 
 PLATFORMS