Register a specific twig-filter for locale specific date

Use the registerMarkupTags method in the Plugin.php to register a twig-filter for a locale specific date.

public function registerMarkupTags()
{
    return [
        'filters' => [
            'germanDate' => function ($date_time, $format) {
                $carbon = new Carbon($date_time);
                setlocale(LC_ALL, 'German');

                return utf8_encode($carbon->formatLocalized($format));
            },
        ],
    ];
}

Now simply use the new filter in your twig files:

{{ '2019-01-16' | germanDate('%e. %B %Y') }} // 1. Januar 2019