Update composer.json

laravel 5.8 support

Author: saqueib

composer.json

@@ -19,7 +19,7 @@
   ],
   "require": {
     "php": ">=5.6.0",
-    "laravel/framework": "~5.4.0|~5.5.0|~5.6.0|~5.7.0"
+    "laravel/framework": "~5.4.0|~5.5.0|~5.6.0|~5.7.0|~5.8.0"
   },
   "require-dev": {
     "orchestra/testbench": "~3.4",