Support Laravel 9

[Shelob9]

I wasn't able to install in Laravel 9, no way to build compatible package.

I did a fork, changed the requriments for PHP, Illuminate packages and Symfony process. Then I tested by adding to composer.json:

"repositories": [
        {
            "type": "vcs",
            "url": "https://github.com/Shelob9/Backup"
        }
    ]

and in require:

        "cornford/backup": "dev-patch-1"

I was able to get the package installed with composer update.

[Shelob9]

The problem with this is the update to Symfony/Process isn't backwards compatible. Need to change how it's used.