Change library path for tota11y

Right now, the tota11y.libraries.yml for this module is setup to load the tota11y JS library from /libraries/tota11y/tota11y.min.js. However, if you are using composer.json to manage your dependencies and download the entire tota11y library from Github, it is hard to configure the library to be downloaded and placed in that folder structure.

Sample composer.json

{
  "repositories": [
    {
      "type": "package",
      "package": {
        "name": "local/tota11y",
        "version": "dev-master",
        "type": "drupal-library",
        "dist": {
          "type": "zip",
          "url": "https://github.com/Khan/tota11y/archive/master.zip"
        }
      }
    }
  ]
}

When the tota11y JS library is downloaded based on this composer.json, the minified copy of the tota11y library will be in: /libraries/tota11y/build/tota11y.min.js. So I propose that we change the path to the library in the libraries.yml to match this path.