Fix image resizing parameters in index.html

[TerezaJvk]

No description provided.

[hdatma]

If I apply the commit, this is what I get.

ERROR error building site: render: [it v1.0.0 guest] failed to render pages: render of "/archive/example.org/www/content/en/_index.md" failed: "/archive/example.org/www/themes/hugo-scroll/layouts/_default/index.html:20:15": execute of template failed: template: index.html:20:15: executing "main" at <$img.Resize>: error calling Resize: failed to resize image "/archive/example.org/www/assets/images/cover-image.webp": must provide Width or Height