chore(deps-dev): bump rexml from 3.2.5 to 3.2.8

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.5 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@v3.2.5...v3.2.8)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -287,7 +287,8 @@ GEM
     rake (13.1.0)
     regexp_parser (2.7.0)
     resolv (0.3.0)
-    rexml (3.2.5)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rouge (4.2.0)
     rspec (3.12.0)
       rspec-core (~> 3.12.0)
@@ -352,6 +353,7 @@ GEM
       actionpack (>= 5.2)
       activesupport (>= 5.2)
       sprockets (>= 3.0.0)
+    strscan (3.1.0)
     swd (2.0.3)
       activesupport (>= 3)
       attr_required (>= 0.0.5)