updated composer.json file

composer.json

@@ -10,7 +10,10 @@
         }
     ],
     "require": {
-        "php": ">=5.4.0"
+        "php": ">=7"
+    },
+    "require-dev": {
+        "laravel/framework": ">=5.5"
     },
     "minimum-stability": "dev",
     "autoload": {