Twig: Sandbox Information Disclosure

[StaffNowa]

Hello, symfony demo have vulnerabilities

!!  1 packages have known vulnerabilities.
!!  
!!  twig/twig (v2.6.2)
!!  ------------------
!!  
!!   * [CVE-NONE-0001][]: Sandbox Information Disclosure
!!  
!!  [CVE-NONE-0001]: https://symfony.com/blog/twig-sandbox-information-disclosure

This can be solved upgrade composer.json file

 "require": {
        ...
        "twig/twig": "^2.7",
        ...
    },

and run

composer update

[yceruto]

See #955

[javiereguiluz]

Closing as fixed by #955. Thanks.