Updating client dependencies. Switching to yarn. (#6433)

* Updating client dependancies. Switching to using yarn.

* Updating React

* Moving pure components to using function syntax (performance gains with newer react version)

* Updating client dependancies.

* Ignore .yarninstall

* Enabling pre-lockfile because it's the entire point of using yarn.

* Removing old webpack config

* Moving to new prop-types

* Fixing ESLint Errors

* Updating jest snapshots.

* Cleaning up package.json

webapp/components/signup/components/signup_email.jsx

@@ -13,6 +13,8 @@ import {loadMe, loginById, createUserWithInvite} from 'actions/user_actions.jsx'
 import * as Utils from 'utils/utils.jsx';
 import Constants from 'utils/constants.jsx';
 
+import PropTypes from 'prop-types';
+
 import React from 'react';
 import {FormattedMessage, FormattedHTMLMessage} from 'react-intl';
 import {browserHistory, Link} from 'react-router/es6';
@@ -22,7 +24,7 @@ import logoImage from 'images/logo.png';
 export default class SignupEmail extends React.Component {
     static get propTypes() {
         return {
-            location: React.PropTypes.object
+            location: PropTypes.object
         };
     }
 

webapp/components/signup/components/signup_ldap.jsx

@@ -10,6 +10,8 @@ import {trackEvent} from 'actions/diagnostics_actions.jsx';
 
 import * as Utils from 'utils/utils.jsx';
 
+import PropTypes from 'prop-types';
+
 import React from 'react';
 import {FormattedMessage, FormattedHTMLMessage} from 'react-intl';
 import {browserHistory, Link} from 'react-router/es6';
@@ -19,7 +21,7 @@ import logoImage from 'images/logo.png';
 export default class SignupLdap extends React.Component {
     static get propTypes() {
         return {
-            location: React.PropTypes.object
+            location: PropTypes.object
         };
     }
 

webapp/components/signup/signup_controller.jsx

@@ -1,3 +1,5 @@
+import PropTypes from 'prop-types';
+
 // Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
@@ -374,5 +376,5 @@ export default class SignupController extends React.Component {
 }
 
 SignupController.propTypes = {
-    location: React.PropTypes.object
+    location: PropTypes.object
 };