Fix DI config for JsonContext (#23)

Author: hgiesenow

README.md

@@ -50,7 +50,7 @@ default:
         - Elbformat\SymfonyBehatBundle\Context\MailerContext
 ```
 ### Mailer
-To make the Test-Mailer work, you need to set the mailer dsn in `config/packages/framework.yaml`
+To make the Test-Mailer work, you need to set the mailer dsn in `config/packages/mailer.yaml`
 ```
 when@test:
     framework:

src/Resources/config/services.yml

@@ -27,6 +27,7 @@ services:
       $strComp: '@Elbformat\SymfonyBehatBundle\Helper\StringCompare'
   Elbformat\SymfonyBehatBundle\Context\JsonContext:
     arguments:
+      $kernel: '@kernel'
       $state: '@Elbformat\SymfonyBehatBundle\Browser\State'
       $arrayComp: '@Elbformat\SymfonyBehatBundle\Helper\ArrayDeepCompare'
   Elbformat\SymfonyBehatBundle\Context\LoggingContext: ~