Bump rexml from 3.2.6 to 3.2.8 in the bundler group across 1 directory

Bumps the bundler group with 1 update in the / directory: [rexml](https://github.com/ruby/rexml).


Updates `rexml` from 3.2.6 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@v3.2.6...v3.2.8)

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

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -74,7 +74,8 @@ GEM
     rainbow (3.1.1)
     rake (13.0.6)
     regexp_parser (2.9.0)
-    rexml (3.2.6)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rspec (3.11.0)
       rspec-core (~> 3.11.0)
       rspec-expectations (~> 3.11.0)
@@ -105,6 +106,7 @@ GEM
       rubocop (~> 1.51)
     ruby-progressbar (1.13.0)
     smart_properties (1.17.0)
+    strscan (3.1.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
     unicode-display_width (2.5.0)