chore(deps): 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]>

Gemfile.lock

@@ -66,7 +66,8 @@ GEM
     regexp_parser (2.5.0)
     reverse_markdown (2.1.1)
       nokogiri
-    rexml (3.2.5)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rouge (3.29.0)
     rspec (3.11.0)
       rspec-core (~> 3.11.0)
@@ -110,6 +111,7 @@ GEM
       unicode-display_width (>= 1.5, < 3.0)
       unicode_utils (~> 1.4)
     strings-ansi (0.2.0)
+    strscan (3.1.0)
     thor (1.2.1)
     tty-color (0.6.0)
     tty-cursor (0.7.1)