.github/workflows/main.yml in toycol-0.0.1 vs .github/workflows/main.yml in toycol-0.1.0

@@ -3,14 +3,17 @@
 on: [push,pull_request]
 
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby: [2.6, 2.7, 3.0, head]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 3.0.0
+        ruby-version: ${{ matrix.ruby }}
         bundler-cache: true
     - name: Run the default task
       run: bundle exec rake