Update rubocop-rspec requirement from ~> 3.4.0 to ~> 3.6.0

Updates the requirements on [rubocop-rspec](https://github.com/rubocop/rubocop-rspec) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop-rspec/releases)
- [Changelog](https://github.com/rubocop/rubocop-rspec/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rspec@v3.4.0...v3.6.0)

---
updated-dependencies:
- dependency-name: rubocop-rspec
  dependency-version: 3.6.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

publify_textfilter_code.gemspec

@@ -26,7 +26,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency "rubocop", "~> 1.77.0"
   s.add_development_dependency "rubocop-performance", "~> 1.23.1"
   s.add_development_dependency "rubocop-rails", "~> 2.32.0"
-  s.add_development_dependency "rubocop-rspec", "~> 3.4.0"
+  s.add_development_dependency "rubocop-rspec", "~> 3.6.0"
   s.add_development_dependency "simplecov", "~> 0.22.0"
   s.add_development_dependency "sqlite3", "~> 1.4"
   s.metadata["rubygems_mfa_required"] = "true"