PHP 8 support, test workflow syntax

.github/workflows/ci.yml

@@ -15,16 +15,23 @@ jobs:
 
     strategy:
       matrix:
+        php:
+          "7.4":
+            - target=php:7.4-cli
+            - version=7.4
+          "8.0":
+            - target=php:8.0.0RC5-cli
+            - version=8.0
         laravel: [
           "^6.0",
           "^7.0",
           "^8.0"
         ]
-    
+
     steps:
     - uses: actions/checkout@v2
     - name: Start docker containers
-      run: docker-compose up -d
+      run: PHP_TARGET=${{ matrix.php.target}} PHP_VESRSION=${{ matrix.php.version }} docker-compose up -d
     - name: Install dependencies
       run: docker-compose exec -T test composer require --no-interaction "laravel/framework:${{ matrix.laravel }}"
     - name: Run tests