Error trying to include sources in my deploy

Per Moovweb XDN Documentation - xdn.config.js, I have modified xdn.config.js with:

module.exports = {
  sources: ['**/*'],
};

However, during a build or deploy, I get the following error:

Error: Failed to load /Users/tristanlee/Projects/react-app/xdn.config.js: XDN configuration validation failed with errors:
1 ) config: should NOT have additional properties ‘sources’