Fix Ruby version consistency and pin RuboCop versions

- Set minimum Ruby version to 3.0 across all configurations
- Updated .rubocop.yml TargetRubyVersion from 2.6 to 3.0
- Updated GitHub Actions workflow to use Ruby 3.0
- Added required_ruby_version >= 3.0.0 to gemspec
- Pinned RuboCop versions for consistency:
  - rubocop ~> 1.81
  - rubocop-rake ~> 0.7
  - rubocop-rspec ~> 3.7
- Updated to use new plugin syntax instead of require

This ensures consistency between CI, local development, and RuboCop
configuration. Ruby 3.0 is a reasonable minimum for modern projects.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

.github/workflows/lint.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: '3.2'
+        ruby-version: '3.0'
         bundler-cache: true
 
     - name: Run RuboCop

.rubocop.yml

@@ -1,9 +1,9 @@
-require:
+plugins:
   - rubocop-rake
   - rubocop-rspec
 
 AllCops:
-  TargetRubyVersion: 2.6
+  TargetRubyVersion: 3.0
   NewCops: enable
   Exclude:
     - 'vendor/**/*'

cypress-on-rails.gemspec

@@ -22,9 +22,12 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'factory_bot', '!= 6.4.5'
   s.add_development_dependency 'vcr'
   s.add_development_dependency 'gem-release'
-  s.add_development_dependency 'rubocop'
-  s.add_development_dependency 'rubocop-rake'
-  s.add_development_dependency 'rubocop-rspec'
+  s.add_development_dependency 'rubocop', '~> 1.81'
+  s.add_development_dependency 'rubocop-rake', '~> 0.7'
+  s.add_development_dependency 'rubocop-rspec', '~> 3.7'
+
+  s.required_ruby_version = '>= 3.0.0'
+
   s.metadata = {
     "bug_tracker_uri"   => "https://github.com/shakacode/cypress-on-rails/issues",
     "changelog_uri"     => "https://github.com/shakacode/cypress-on-rails/blob/master/CHANGELOG.md",