Use composer to copy .env.example after its done installing packages. (#1073)

composer.json

@@ -80,11 +80,8 @@
         "post-autoload-dump": [
             "Illuminate\\Foundation\\ComposerScripts::postAutoloadDump"
         ],
-        "post-root-package-install": [
-            "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
-        ],
-        "post-create-project-cmd": [
-            "@php artisan key:generate --ansi"
+        "post-install-cmd": [
+            "php -r \"file_exists('.env') || copy('.env.example', '.env');\""
         ],
         "dev": [
             "Composer\\Config::disableProcessTimeout",