Laravel used Carbon (I think).
You can install Carbon. For example via composer
$ composer require nesbot/carbon
and create filter
$di->set('volt', function ($view, $di) {
    $volt = new VoltEngine($view, $di);
    $volt->setOptions(array(
        "compiledPath" => APP_PATH . "cache/volt/",
    ));
    $compiler = $volt->getCompiler();
    $compiler->addFilter('diffForHumans', function($resolvedArgs, $exprArgs){
        return '\Carbon\Carbon::createFromFormat("Y-m-d H:i:s", '.$resolvedArgs.')->diffForHumans()';
    });
    return $volt;
}, true);
$di->set('view', function () use ($config) {
    $view = new View();
    $view->setViewsDir(APP_PATH . $config->application->viewsDir);
    $view->registerEngines(array(
        ".volt" => 'volt'
    ));
    return $view;
});
In Volt template
Registered: {{ user.created_at|diffForHumans }}<br>