chore(deps): bump rexml from 3.2.6 to 3.2.8

Bumps [rexml](https://github.com/ruby/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
...

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

Gemfile.lock

@@ -73,7 +73,8 @@ GEM
     regexp_parser (2.9.1)
     reverse_markdown (2.1.1)
       nokogiri
-    rexml (3.2.6)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     roda (3.80.0)
       rack
     rspec (3.12.0)
@@ -127,6 +128,7 @@ GEM
       simplecov_json_formatter (~> 0.1)
     simplecov-html (0.12.3)
     simplecov_json_formatter (0.1.4)
+    strscan (3.1.0)
     thor (1.3.1)
     tilt (2.3.0)
     tzinfo (2.0.6)