Unable to find asset "./bootswatch/_variables.scss"

[abedo]

After downloading latest application, and running "composer install", the homepage lacks of any style, and there is an error in logs:

Uncaught PHP Exception Symfony\Component\AssetMapper\Exception\RuntimeException: "Unable to find asset "./bootswatch/_variables.scss" referenced in "/symfony-demos/symfony-demo-73/assets/styles/_variables.scss". The file "/symfony-demos/symfony-demo-73/assets/styles/bootswatch/_variables.scss" exists, but it is not in a mapped asset path. Add it to the "paths" config." at CssAssetUrlCompiler.php

[javiereguiluz]

Closed by #1620.