Bump rexml from 3.3.3 to 3.3.9

Bumps [rexml](https://github.com/ruby/rexml) from 3.3.3 to 3.3.9.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.3.3...v3.3.9)

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

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

Gemfile.lock

@@ -340,8 +340,7 @@ GEM
       http-cookie (>= 1.0.2, < 2.0)
       mime-types (>= 1.16, < 4.0)
       netrc (~> 0.8)
-    rexml (3.3.3)
-      strscan
+    rexml (3.3.9)
     rspec-core (3.13.0)
       rspec-support (~> 3.13.0)
     rspec-expectations (3.13.0)
@@ -395,7 +394,6 @@ GEM
     sqlite3 (1.7.2)
       mini_portile2 (~> 2.8.0)
     stringio (3.1.0)
-    strscan (3.1.0)
     telegram-bot-ruby (2.0.0)
       dry-struct (~> 1.6)
       faraday (~> 2.0)