Add Laravel 5.6 support

Author: Andrey Helldar

composer.json

@@ -22,14 +22,14 @@
     },
     "require": {
         "php": ">=7.0",
-        "illuminate/http": "5.5.*",
-        "illuminate/routing": "5.5.*",
-        "illuminate/session": "5.5.*",
-        "illuminate/support": "5.5.*",
-        "illuminate/pipeline": "5.5.*"
+        "illuminate/http": "^5.5",
+        "illuminate/routing": "^5.5",
+        "illuminate/session": "^5.5",
+        "illuminate/support": "^5.5",
+        "illuminate/pipeline": "^5.5"
     },
     "require-dev": {
-        "phpunit/phpunit": "~6.0",
+        "phpunit/phpunit": "~6.0|~7.0",
         "graham-campbell/testbench": "^4.0",
         "mockery/mockery": "dev-master"
     },