@lowest and @latest is not respected when project provides explicit checks

[boesing]

Bug Report

Q	A
Version(s)	1.11.4

Summary

I am currently working on providing integration tests in #62
There, I've seen that @lowest and @latest is not properly handled by the matrix action when it comes to explicit checks provided by the projects .laminas-ci.json

Current behavior

When @lowest and/or @latest is used for job.php, the action does skip that job:

::warning::Invalid job provided; no PHP version or unknown PHP version specified: {"php":"@lowest","dependencies":"locked","command":"vendor/bin/phpunit"}
::warning::Invalid job provided; no PHP version or unknown PHP version specified: {"php":"@latest","dependencies":"locked","command":"vendor/bin/phpunit"}

How to reproduce

.laminas-ci.json

{
    "checks": [
        {
            "name": "PHPUnit with locked dependencies on lowest supported PHP version",
            "job": {
                "php": "@lowest",
                "dependencies": "locked",
                "command": "vendor/bin/phpunit"
            }
        },
        {
            "name": "PHPUnit with locked dependencies on lowest supported PHP version",
            "job": {
                "php": "@latest",
                "dependencies": "locked",
                "command": "vendor/bin/phpunit"
            }
        }
    ]
}

Expected behavior

Matrix does not report a warning for @lowest or @latest and properly uses the lowest and latest supported PHP version by the project within the job declaration.

[boesing]

Will be fixed with #83