Bump rexml from 3.2.6 to 3.3.6

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.6 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@v3.2.6...v3.3.6)

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

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -63,7 +63,8 @@ GEM
     rainbow (3.1.1)
     rake (13.0.6)
     regexp_parser (2.8.1)
-    rexml (3.2.6)
+    rexml (3.3.6)
+      strscan
     rspec (3.12.0)
       rspec-core (~> 3.12.0)
       rspec-expectations (~> 3.12.0)
@@ -93,6 +94,7 @@ GEM
       rubocop-ast (>= 0.7.1)
     ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.5)
+    strscan (3.1.0)
     unicode-display_width (1.8.0)
     zeitwerk (2.6.12)