add github actions CI configuration

Author: ddrv

.github/workflows/ci.yml

@@ -0,0 +1,33 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        php: [7.0, 7.1, 7.2, 7.3, 7.4, 8.0]
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          coverage: none
+
+      - name: Validate composer.json and composer.lock
+        run: composer validate
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-progress --no-interaction --no-suggest
+
+      - name: Check code style
+        run: vendor/bin/phpcs
+
+      - name: Run test suite
+        run: vendor/bin/phpunit