Add an AboutCommand return code

[zoglo]

Description

• Fixes #817

• Also uses return Constants for better readability

Return Constants

see: https://tldp.org/LDP/abs/html/exitcodes.html

• Command::SUCCESS = 0;
• Command::FAILURE = 1;
• Command::INVALID = 2;

They exist in symfony/console 5.4 and still exist in 7.2

5.4: https://github.com/symfony/console/blob/6473d441a913cb997123b59ff2dbe3d1cf9e11ba/Command/Command.php#L35-L38

7.2: https://github.com/symfony/console/blob/b71a095124de660d598da3031c39e2790f64e28a/Command/Command.php#L37-L40

[aschempp]

Thank you @zoglo