Build(deps): Bump concurrent-ruby from 1.1.8 to 1.1.9

Bumps [concurrent-ruby](https://github.com/ruby-concurrency/concurrent-ruby) from 1.1.8 to 1.1.9.
- [Release notes](https://github.com/ruby-concurrency/concurrent-ruby/releases)
- [Changelog](https://github.com/ruby-concurrency/concurrent-ruby/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ruby-concurrency/concurrent-ruby/compare/v1.1.8...v1.1.9)

---
updated-dependencies:
- dependency-name: concurrent-ruby
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -92,7 +92,7 @@ GEM
     chunky_png (1.4.0)
     coderay (1.1.3)
     colored2 (3.1.2)
-    concurrent-ruby (1.1.8)
+    concurrent-ruby (1.1.9)
     connection_pool (2.2.5)
     cose (1.2.0)
       cbor (~> 0.5.9)