Setup Github Actions for CI

.github/workflows/php.yml

@@ -0,0 +1,29 @@
+name: CI
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+        php: ['latest', '8.1', '7.4']
+
+    runs-on: ${{ matrix.os }}
+    name: Test on ${{ matrix.os }}, PHP ${{ matrix.php }} 
+
+    steps:
+    - uses: actions/checkout@v4
+    - uses: php-actions/composer@v6
+
+    - name: PHPUnit tests
+      uses: php-actions/phpunit@v4
+      with:
+        php_version: ${{ matrix.php }}