ci: add GitHub Actions workflow for testing PHP code

.github/workflows/test.yml

@@ -0,0 +1,23 @@
+name: Tests
+on: ['push', 'pull_request']
+
+jobs:
+  ci:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.4
+          tools: composer:v2
+          coverage: xdebug
+
+      - name: Install Dependencies
+        run: composer install --no-interaction --prefer-dist --optimize-autoloader
+
+      - name: Tests
+        run: ./vendor/bin/pest --ci