added laravel 5.8 support

Author: bhavinjr

composer.json

@@ -15,7 +15,7 @@
     "minimum-stability": "stable",
     "require": {
         "php": ">=5.6.0",
-        "illuminate/support": "5.1.*|5.2.*|5.3.*|5.4.*|5.5.*|5.6.*|5.7.*"
+        "illuminate/support": "5.1.*|5.2.*|5.3.*|5.4.*|5.5.*|5.6.*|5.7.*|5.8.*"
     },
     "autoload": {
         "psr-4": {