Update concurrent-ruby requirement from < 1.3.5 to < 1.3.6

Updates the requirements on [concurrent-ruby](https://github.com/ruby-concurrency/concurrent-ruby) to permit the latest version.
- [Release notes](https://github.com/ruby-concurrency/concurrent-ruby/releases)
- [Changelog](https://github.com/ruby-concurrency/concurrent-ruby/blob/master/CHANGELOG.md)
- [Commits](ruby-concurrency/concurrent-ruby@v0.0.1...v1.3.5)

---
updated-dependencies:
- dependency-name: concurrent-ruby
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Gemfile

@@ -6,6 +6,6 @@ gemspec
 
 gem "rubocop", require: false
 gem "codeclimate-test-reporter"
-gem "concurrent-ruby", "< 1.3.5"
+gem "concurrent-ruby", "< 1.3.6"
 
 gem "rails", "~> #{ENV.fetch('RAILS_VERSION', '8.0')}"