Bump rexml from 3.2.5 to 3.2.6 (#344)

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.5 to 3.2.6.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.2.5...v3.2.6)

---
updated-dependencies:
- dependency-name: rexml
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: jheikes515 <[email protected]>

Gemfile.lock

@@ -15,7 +15,7 @@ GEM
       base64 (>= 0.1.0)
       rack (~> 2.2, >= 2.2.4)
     rack-ssl-enforcer (0.2.9)
-    rexml (3.2.5)
+    rexml (3.2.6)
     ruby2_keywords (0.0.5)
     sinatra (3.2.0)
       mustermann (~> 3.0)