Merge branch '2.3' into 2.7

* 2.3:
  disable server:run cmd without Process component
  Suggested Process dependency

Author: fabpot

Command/ServerRunCommand.php

@@ -34,6 +34,10 @@ public function isEnabled()
             return false;
         }
 
+        if (!class_exists('Symfony\Component\Process\Process')) {
+            return false;
+        }
+
         return parent::isEnabled();
     }
 

composer.json

@@ -54,6 +54,7 @@
         "symfony/serializer": "For using the serializer service",
         "symfony/validator": "For using validation",
         "symfony/yaml": "For using the debug:config and lint:yaml commands",
+        "symfony/process": "For using the server:run command",
         "doctrine/cache": "For using alternative cache drivers"
     },
     "autoload": {