add ruby 4 to ci testing

Author: mjansing

.github/workflows/ci.yml

@@ -7,19 +7,19 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.1", "3.2", "3.3", "3.4"]
+        ruby: ["3.1", "3.2", "3.3", "3.4", "4.0"]
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
 
       - name: Caching dependencies
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: vendor/bundle
           key: bundle-use-ruby-${{ runner.os }}-${{ matrix.ruby }}-${{ hashFiles('**/Gemfile.lock') }}

Gemfile

@@ -20,6 +20,7 @@ gemspec
 gem 'rake'
 gem 'rdoc'
 gem 'activesupport'
+gem 'ostruct'
 
 group :test do
   gem 'mutex_m'