chore(deps): bump rexml from 3.3.4 to 3.3.6 in /canaries/example (#3830)

Bumps [rexml](https://github.com/ruby/rexml) from 3.3.4 to 3.3.6.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.3.4...v3.3.6)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

canaries/example/Gemfile.lock

@@ -168,7 +168,7 @@ GEM
       trailblazer-option (>= 0.1.1, < 0.2.0)
       uber (< 0.2.0)
     retriable (3.1.2)
-    rexml (3.3.4)
+    rexml (3.3.6)
       strscan
     rouge (2.0.7)
     ruby2_keywords (0.0.5)