add template env

Author: LTaooo

.env.simple

@@ -0,0 +1,4 @@
+APP_NAME=MicroPHP
+APP_ENV=local
+SERVER_DRIVER=workerman
+

composer.json

@@ -26,6 +26,9 @@
         "phpunit/phpunit": "^10.2"
     },
     "scripts": {
+        "post-root-package-install": [
+            "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
+        ],
         "cs": [
             "./vendor/bin/php-cs-fixer fix --verbose"
         ]