Updating client dependancies and ESLint (#2954)

* Updating client dependancies

* Fixing eslint errors with updates

* Updating eslint

webapp/tests/client_post.test.jsx

@@ -1,13 +1,6 @@
 // Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
-/* eslint-disable no-console */
-/* eslint-disable global-require */
-/* eslint-disable func-names */
-/* eslint-disable prefer-arrow-callback */
-/* eslint-disable no-magic-numbers */
-/* eslint-disable no-unreachable */
-
 import assert from 'assert';
 import TestHelper from './test_helper.jsx';