Merge pull request #3302 from amatsuda/ci

CI against Ruby 3.1 and 3.2

Author: amatsuda

.github/workflows/ruby.yml

@@ -17,6 +17,8 @@ jobs:
         ruby:
           - 2.7
           - "3.0"
+          - 3.1
+          - 3.2
         gemfile:
           - gemfiles/Gemfile-rails.5.2.x
           - gemfiles/Gemfile-rails.6.0.x
@@ -26,6 +28,10 @@ jobs:
             gemfile: gemfiles/Gemfile-rails.6.1.x
           - ruby: "3.0"
             gemfile: gemfiles/Gemfile-rails.5.2.x
+          - ruby: 3.1
+            gemfile: gemfiles/Gemfile-rails.5.2.x
+          - ruby: 3.2
+            gemfile: gemfiles/Gemfile-rails.5.2.x
         experimental: [false]
         include:
           - ruby: 2.7
@@ -45,6 +51,7 @@ jobs:
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
+          rubygems: latest
           bundler-cache: true # Run "bundle install", and cache the result automatically.
 
       - name: Ruby specs