Bump rexml from 3.2.5 to 3.3.3 (#16)

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.5 to 3.3.3.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.2.5...v3.3.3)

---
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>
Co-authored-by: Hans Schnedlitz <hello@hansschnedlitz.com>

Author: dependabot[bot]

Gemfile.lock

@@ -63,7 +63,8 @@ GEM
     rainbow (3.0.0)
     rake (13.0.1)
     regexp_parser (1.7.1)
-    rexml (3.2.5)
+    rexml (3.3.3)
+      strscan
     rmagick (4.1.2)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
@@ -99,6 +100,7 @@ GEM
     simplecov-html (0.12.3)
     simplecov_json_formatter (0.1.4)
     sqlite3 (1.4.2)
+    strscan (3.1.0)
     tzinfo (2.0.4)
       concurrent-ruby (~> 1.0)
     unf (0.1.4)