Upgrading symfony/console dependency to latest stable (4.0)

Author: craigruks

composer.json

@@ -11,7 +11,7 @@
     ],
     "require": {
         "php": ">=5.6",
-        "symfony/console": "~2.8|~3.0"
+        "symfony/console": "~2.8|~3.0|~4.0"
     },
     "require-dev": {
         "composer/composer": "1.0.*@dev",