Add native php linting into CI

.github/workflows/lint.yml

@@ -0,0 +1,20 @@
+name: Lint
+on: pull_request
+
+jobs:
+  php-linters:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php-versions: ['7.3', '7.4', '8.0']
+    name: php${{ matrix.php-versions }} lint
+    steps:
+      - name: Checkout
+        uses: actions/checkout@master
+      - name: Set up php${{ matrix.php-versions }}
+        uses: shivammathur/setup-php@master
+        with:
+          php-version: ${{ matrix.php-versions }}
+          coverage: none
+      - name: Lint
+        run: bin/composer.phar run lint