Adjust testing method to work with CI/CD

Author: Vectorial1024

README.md

@@ -133,5 +133,5 @@ composer update
 Then:
 
 ```sh
-./vendor/bin/phpunit test
+composer run-script test
 ```

composer.json

@@ -28,5 +28,8 @@
     },
     "require-dev": {
         "phpunit/phpunit": "11"
+    },
+    "scripts": {
+        "test": "vendor/bin/phpunit test"
     }
 }