yoanm#85: fix Symfony kernel for Behat

Author: klimov-paul

features/demo_app/src/AbstractKernel.php

@@ -31,7 +31,7 @@ public function registerBundles(): iterable
     /**
      * {@inheritdoc}
      */
-    public function getCacheDir()
+    public function getCacheDir(): string
     {
         // Use a specific cache for each kernels
         if (null === $this->customCacheDir) {
@@ -44,15 +44,15 @@ public function getCacheDir()
     /**
      * {@inheritdoc}
      */
-    public function getLogDir()
+    public function getLogDir(): string
     {
         return $this->getProjectDir().'/var/log';
     }
 
     /**
      * {@inheritdoc}
      */
-    public function getProjectDir()
+    public function getProjectDir(): string
     {
         return realpath(__DIR__.'/../');
     }
@@ -86,7 +86,7 @@ protected function configureContainer(ContainerBuilder $container, LoaderInterfa
      *
      * @return string The container class
      */
-    protected function getContainerClass()
+    protected function getContainerClass(): string
     {
         // In order to avoid collisions between kernels use a dedicated name
         return parent::getContainerClass().Container::camelize($this->getConfigDirectoryName());