add laravel 5.8 supprot (martinlindhe#77)

Author: Raymonf

composer.json

@@ -12,8 +12,8 @@
     ],
     "require": {
         "php": ">=5.5.0",
-        "illuminate/console": "~5.1.0|~5.2.0|~5.3.0|~5.4.0|~5.5.0|~5.6.0|~5.7.0",
-        "illuminate/support": "~5.1.0|~5.2.0|~5.3.0|~5.4.0|~5.5.0|~5.6.0|~5.7.0"
+        "illuminate/console": "~5.1.0|~5.2.0|~5.3.0|~5.4.0|~5.5.0|~5.6.0|~5.7.0|~5.8.0",
+        "illuminate/support": "~5.1.0|~5.2.0|~5.3.0|~5.4.0|~5.5.0|~5.6.0|~5.7.0|~5.8.0"
     },
     "require-dev": {
         "phpunit/phpunit": "~4.7"