[Tree] Labs logo missing

[Tacsipacsi]

tree.html links to https://wikitech.wikimedia.org/w/images/c/cf/Labslogo_thumb.png, which is now stored on upload.wikimedia.org, so referencing to the old URL causes a 404 error and a missing image. Also, there’s no need for a protocol-relative URL, the HTTP version redirects to HTTPS anyway.