How to create a collection that ends with .html, eg: /posts/post.html

[filisko]

Hi,

How can I create a collection that ends with .html on the URL?

I tried this but the .HTML part is not considered:

    'collections' => [
        'posts' => [
            'path' => '{date|Y/m/d}/{filename}.html',
            'author' => 'Tighten',
        ],
    ],