Bump rexml from 3.2.5 to 3.3.6

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.5 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@v3.2.5...v3.3.6)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -81,7 +81,8 @@ GEM
       http-cookie (>= 1.0.2, < 2.0)
       mime-types (>= 1.16, < 4.0)
       netrc (~> 0.8)
-    rexml (3.2.5)
+    rexml (3.3.6)
+      strscan
     rubocop (1.30.1)
       parallel (~> 1.10)
       parser (>= 3.1.0.0)
@@ -125,6 +126,7 @@ GEM
     snaky_hash (2.0.0)
       hashie
       version_gem (~> 1.1)
+    strscan (3.1.0)
     typhoeus (1.4.0)
       ethon (>= 0.9.0)
     unf (0.1.4)