Fix deprecation error

Author: enumag

composer.json

@@ -16,7 +16,7 @@
         "codeception/codeception": "^2.3.2",
         "nette/bootstrap": "^3.0.0",
         "nette/di": "^3.0.0",
-        "nette/http": "^3.0.0"
+        "nette/http": "^3.0.0@dev"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^2.7.0@dev",