Add Laravel 5.8 support

Author: driesvints

composer.json

@@ -18,14 +18,14 @@
         "ext-json": "*",
         "firebase/php-jwt": "~3.0|~4.0|~5.0",
         "guzzlehttp/guzzle": "~6.0",
-        "illuminate/auth": "~5.6.0|~5.7.0",
-        "illuminate/console": "~5.6.0|~5.7.0",
-        "illuminate/container": "~5.6.0|~5.7.0",
-        "illuminate/contracts": "~5.6.0|~5.7.0",
-        "illuminate/database": "~5.6.0|~5.7.0",
-        "illuminate/encryption": "~5.6.0|~5.7.0",
-        "illuminate/http": "~5.6.0|~5.7.0",
-        "illuminate/support": "~5.6.0|~5.7.0",
+        "illuminate/auth": "~5.6.0|~5.7.0|~5.8.0",
+        "illuminate/console": "~5.6.0|~5.7.0|~5.8.0",
+        "illuminate/container": "~5.6.0|~5.7.0|~5.8.0",
+        "illuminate/contracts": "~5.6.0|~5.7.0|~5.8.0",
+        "illuminate/database": "~5.6.0|~5.7.0|~5.8.0",
+        "illuminate/encryption": "~5.6.0|~5.7.0|~5.8.0",
+        "illuminate/http": "~5.6.0|~5.7.0|~5.8.0",
+        "illuminate/support": "~5.6.0|~5.7.0|~5.8.0",
         "league/oauth2-server": "^7.0",
         "phpseclib/phpseclib": "^2.0",
         "symfony/psr-http-message-bridge": "~1.0",