added phpunit github action

Author: staabm

.github/workflows/tests.yml

@@ -0,0 +1,35 @@
+name: Static analysis
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+
+  phpstan:
+    name: PHPStan
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    strategy:
+      matrix:
+        php-version: ['8.0', '8.1', '8.2']
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup PHP
+        id: setup-php
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          coverage: none
+
+      - uses: "ramsey/composer-install@v2"
+        with:
+          composer-options: "--prefer-dist --no-progress --no-suggest"
+
+      - run: composer require redaxo/source
+
+      - run: composer test