Add GitHub Actions test workflow

.github/workflows/tests.yml

@@ -0,0 +1,31 @@
+name: Tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        php: ['8.1', '8.2', '8.3', '8.4']
+
+    name: PHP ${{ matrix.php }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          coverage: none
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-progress
+
+      - name: Run tests
+        run: composer test