Update deps and install laravel/browser-kit-testing

Author: jbrooksuk

composer.json

@@ -58,6 +58,7 @@
         "filp/whoops": "^2.1",
         "fzaninotto/faker": "^1.6",
         "graham-campbell/testbench-core": "^1.1",
+        "laravel/browser-kit-testing": "^1.0",
         "mockery/mockery": "0.9.7",
         "phpunit/phpunit": "5.7.6",
         "symfony/css-selector": "^3.1",
@@ -113,6 +114,6 @@
             "dev-master": "2.4-dev"
         }
     },
-    "minimum-stability": "stable",
+    "minimum-stability": "dev",
     "prefer-stable": true
 }