Test against Ruby 3.4 (#49)

Author: tagliala

.github/workflows/rubocop.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: '3.3'
+        ruby-version: '3.4'
         rubygems: latest
         bundler-cache: true
     - name: RuboCop

.github/workflows/ruby.yml

@@ -16,7 +16,7 @@ jobs:
 
     strategy:
       matrix:
-        ruby-version: ['2.3', '2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3']
+        ruby-version: ['2.3', '2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3', '3.4']
         channel: [stable]
 
         include: