chore(deps-dev): bump rexml from 3.2.5 to 3.2.8 (#68)

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] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -21,7 +21,8 @@ GEM
     rainbow (3.1.1)
     rake (12.3.3)
     regexp_parser (2.6.0)
-    rexml (3.2.5)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rspec (3.8.0)
       rspec-core (~> 3.8.0)
       rspec-expectations (~> 3.8.0)
@@ -59,6 +60,7 @@ GEM
       simplecov_json_formatter (~> 0.1)
     simplecov-html (0.12.3)
     simplecov_json_formatter (0.1.4)
+    strscan (3.1.0)
     typhoeus (1.4.0)
       ethon (>= 0.9.0)
     unicode-display_width (2.3.0)