code: function getCredentials(gruntOptions) {
      if (gruntOptions.authKey && grunt.file.exists('.ftpauth')) {
        return JSON.parse(grunt.file.read('.ftpauth'))[gruntOptions.authKey];
      } else if (gruntOptions.username && gruntOptions.password) {
        return { username: gruntOptions.username, password: gruntOptions.password };
      } else {
        // Warn the user we are attempting an anonymous login
        grunt.log.warn(messages.anonymousLogin);
        return { username: null, password: null };
      }
    }
docs: Based off of whats in the options, create a credentials object
  @param {object} options - grunt options provided to the plugin
  @return {object} {username: '...', password: '...'}