Bump rexml from 3.2.5 to 3.3.3

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>

Gemfile.lock

@@ -68,7 +68,8 @@ GEM
     rbtree (0.4.4)
     redis (4.3.1)
     regexp_parser (2.1.1)
-    rexml (3.2.5)
+    rexml (3.3.3)
+      strscan
     rspec (3.10.0)
       rspec-core (~> 3.10.0)
       rspec-expectations (~> 3.10.0)
@@ -106,6 +107,7 @@ GEM
     sorted_set (1.0.3)
       rbtree
       set (~> 1.0)
+    strscan (3.1.0)
     thor (1.1.0)
     unicode-display_width (2.0.0)
     vault (0.16.0)