code: function updateChangedCssFiles() {
  		let hash, filePath;
  		const changedFiles = [];
  		for ( filePath in publicCssFiles ) {
  			hash = md5File.sync( filePath );
  			if ( hash !== publicCssFiles[ filePath ] ) {
  				publicCssFiles[ filePath ] = hash;
  				changedFiles.push( path.basename( filePath ) );
  			}
  		}
  
  		return changedFiles;
  	}
docs: Updates the MD5 hash of the public CSS files and returns the changed ones
  in a list.
  @returns {Array} an array of changed files (string)