build(deps-dev): bump rexml from 3.2.7 to 3.2.8 (#1118)

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.7 to 3.2.8.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.2.7...v3.2.8)

---
updated-dependencies:
- dependency-name: rexml
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -52,7 +52,7 @@ GEM
     rainbow (3.1.1)
     rake (13.2.1)
     regexp_parser (2.9.2)
-    rexml (3.2.7)
+    rexml (3.2.8)
       strscan (>= 3.0.9)
     rmagick (5.5.0)
       observer (~> 0.1)