Bump rexml from 3.2.6 to 3.3.0

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.6 to 3.3.0.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.2.6...v3.3.0)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -320,7 +320,8 @@ GEM
     responders (3.1.0)
       actionpack (>= 5.2)
       railties (>= 5.2)
-    rexml (3.2.6)
+    rexml (3.3.0)
+      strscan
     rouge (4.1.2)
     rspec-core (3.12.2)
       rspec-support (~> 3.12.0)
@@ -413,6 +414,7 @@ GEM
       activesupport (>= 5.2)
       sprockets (>= 3.0.0)
     stringio (3.1.0)
+    strscan (3.1.0)
     sys-uname (1.2.3)
       ffi (~> 1.1)
     terminal-table (3.0.2)