Start adding github action

Author: shabbyrobe

.github/workflows/php.yml

@@ -0,0 +1,41 @@
+name: Test docopt.php
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php-version: ["7.2", "7.3", "7.4", "8.0"]    
+        
+    steps:
+    - name: Setup PHP ${{ matrix.php-version }}
+      uses: shivammathur/setup-php@15c43e89cdef867065b0213be354c2841860869e
+      with:
+        php-version: ${{ matrix.php-version }}
+    
+    - uses: actions/checkout@v3
+      with:
+        submodules: true
+
+    - 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: php test.php