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] <support@github.com>

Gemfile.lock

@@ -265,7 +265,8 @@ GEM
     responders (3.1.0)
       actionpack (>= 5.2)
       railties (>= 5.2)
-    rexml (3.2.6)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rover-df (0.3.4)
       numo-narray (>= 0.9.1.9)
     rubocop (1.56.1)
@@ -341,6 +342,7 @@ GEM
       rubocop-thread_safety
     stimulus-rails (1.2.2)
       railties (>= 6.0.0)
+    strscan (3.1.0)
     tabreader (1.0.1)
     thor (1.3.1)
     timeout (0.4.1)