chore(deps-dev): bump rexml from 3.2.4 to 3.2.8

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.4 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@v3.2.4...v3.2.8)

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

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

Gemfile.lock

@@ -62,7 +62,8 @@ GEM
     rb-inotify (0.10.0)
       ffi (~> 1.0)
     regexp_parser (2.0.0)
-    rexml (3.2.4)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rspec (3.10.0)
       rspec-core (~> 3.10.0)
       rspec-expectations (~> 3.10.0)
@@ -100,6 +101,7 @@ GEM
       unicode-display_width (~> 1.5)
       unicode_utils (~> 1.4)
     strings-ansi (0.2.0)
+    strscan (3.1.0)
     thor (1.0.1)
     tty-color (0.6.0)
     tty-pager (0.14.0)