Deprecated sensiolabs/security-checker

[chalasr]

Hi there 👋
https://github.com/sensiolabs/security-checker is deprecated in favor of Symfony CLI's security:check command.
Shall we deprecate the security-checker docker image as well? Or we could make it use https://github.com/fabpot/local-php-security-checker (actively maintained)

[nervo]

Hi @chalasr 🦬

@greedybro is in a big cleanup mood, and this image will soon disappear :)