I had set-up the wrong credentials in ACCESS_TOKEN. With version 1.1 when doing git push, it printed the Git error, and the process failed.

With this new version in PHP, doing exec('git push --quiet origin ' . $config->getBranch()); also produces a Git error, but it is just printed on screen; the GitHub Action does not fail, so I get the ✔️ at the end of the run.

To fix it, something like this could work:

$output = [];
$result_code = 0;
$result = $exec('git push --quiet origin ' . $config->getBranch(), $output, $result_code);
if ($result === false) {
    die('Command failed: ' . implode(PHP_EOL, $output));
}

Or return $result_code?