ci.yml in yt_dlp-0.2.0

- old
+ new

@@ -7,15 +7,18 @@
     branches: [ main ]
 
 jobs:
   ci:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby-version: ['3.1', '3.0', '2.7', 2.6]
     steps:
-      - uses: actions/checkout@v2
-      - name: Set up Ruby
+      - uses: actions/checkout@v3
+      - name: Set up Ruby ${{ matrix.ruby-version }}
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.6
+          ruby-version: ${{ matrix.ruby-version }}
       - name: Install dependencies
         run: bundle install
       - name: Run tests
         run: bundle exec rake ci
         env:
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