add ci workflow to run tests on supported php versions (#71)

Author: smhg

.github/workflows/ci.yml

@@ -0,0 +1,46 @@
+name: Run tests
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php-versions: ['7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4']
+    name: Run tests on PHP ${{ matrix.php-versions }}
+
+    steps:
+    - name: Install PHP
+      uses: shivammathur/setup-php@v2
+      with:
+        php-version: ${{ matrix.php-versions }}
+        extensions: json
+
+    - uses: actions/checkout@v4
+
+    - name: Validate composer.json and composer.lock
+      run: composer validate --strict
+
+    - name: Cache Composer packages
+      id: composer-cache
+      uses: actions/cache@v3
+      with:
+        path: vendor
+        key: ${{ runner.os }}-php-${{ hashFiles('**/composer.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-php-
+
+    - name: Install dependencies
+      run: composer install --prefer-dist --no-progress
+
+    - name: Run test suite
+      run: composer run-script test