Bump rexml from 3.3.3 to 3.3.6 (#2630)

Bumps [rexml](https://github.com/ruby/rexml) from 3.3.3 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@v3.3.3...v3.3.6)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -114,7 +114,7 @@ GEM
     open4 (1.3.4)
     public_suffix (4.0.6)
     rchardet (1.8.0)
-    rexml (3.3.3)
+    rexml (3.3.6)
       strscan
     ruby-macho (1.4.0)
     ruby2_keywords (0.0.4)