Add multi-ruby test workflow

Author: codenamev

.github/workflows/multi-ruby-tests.yml

@@ -0,0 +1,24 @@
+name: Tests
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  test:
+    strategy:
+      fail-fast: true
+      matrix:
+        os: [ ubuntu-latest, macos-latest ]
+        ruby: ['2.6.9', '2.7.5', '3.0.3', '3.1.0 ']
+    runs-on: ${{ matrix.os }}
+    steps:
+    - uses: actions/checkout@v2
+    - uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+        bundler-cache: true
+    - name: Run Tests for Ruby ${{ matrix.ruby }} on ${{ matrix.os }}
+      run: bundle exec rake