Updated symfony/console to require v2 or v3

Previously, only symfony/console v2 was supported, causing some
collision with projects that use v3

Author: Roelof Roos

composer.json

@@ -19,7 +19,7 @@
         "php": ">=5.3",
         "ext-curl": "*",
         "satooshi/php-coveralls": "^1.0",
-        "symfony/console": "^2.0"
+        "symfony/console": "^2.0|^3.0"
     },
     "require-dev": {
         "phpunit/phpunit": "3.7.*@stable",