README instructions for Asset Packagist are incomplete

The README.md file for 3.0.1 has instructions on how to use Composer to install libraries like jQuery Simple Color, but the instructions are incomplete.

Specifically, these lines need to be added to the "repositories" section of composer.json:

"repositories": [
    {
        "type": "composer",
        "url": "https://asset-packagist.org"
    }
]

Source: https://asset-packagist.org