Require Laravel 5.5

This preset works only on laravel framework 5.5+, so require
the framework instead of PHP 7.0

Author: deeshrestha

composer.json

@@ -4,7 +4,7 @@
     "keywords": ["laravel", "preset", "zurb-foundation", "foundation"],
     "license": "MIT",
     "require": {
-        "php": ">=7.0.0"
+        "laravel/framework": "5.5.*"
     },
     "autoload": {
         "psr-4": {