https://github.com/Laravelium/laravel-sitemap

add the following to your composer.json file :

For Laravel 5.7

"laravelium/sitemap": "3.0.*"

For Laravel 5.6

"laravelium/sitemap": "2.8.*"

For Laravel 5.5

"laravelium/sitemap": "2.7.*"

Publish needed assets (styles, views, config files) :

php artisan vendor:publish --provider="Laravelium\Sitemap\SitemapServiceProvider"
 

Note: Composer won't update them after composer update, you'll need to do it manually!