Bump rexml from 3.4.1 to 3.4.2 in /examples/ruby

Bumps [rexml](https://github.com/ruby/rexml) from 3.4.1 to 3.4.2.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.4.1...v3.4.2)

---
updated-dependencies:
- dependency-name: rexml
  dependency-version: 3.4.2
  dependency-type: indirect
...

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

Author: dependabot[bot]

examples/ruby/Gemfile.lock

@@ -17,7 +17,7 @@ GEM
     rainbow (3.1.1)
     rake (13.3.0)
     regexp_parser (2.11.2)
-    rexml (3.4.1)
+    rexml (3.4.2)
     rspec (3.13.1)
       rspec-core (~> 3.13.0)
       rspec-expectations (~> 3.13.0)