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/suggestion/suggestion.jsx

@@ -1,3 +1,5 @@
+import PropTypes from 'prop-types';
+
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
@@ -6,11 +8,11 @@ import React from 'react';
 export default class Suggestion extends React.Component {
     static get propTypes() {
         return {
-            item: React.PropTypes.object.isRequired,
-            term: React.PropTypes.string.isRequired,
-            matchedPretext: React.PropTypes.string.isRequired,
-            isSelection: React.PropTypes.bool,
-            onClick: React.PropTypes.func
+            item: PropTypes.object.isRequired,
+            term: PropTypes.string.isRequired,
+            matchedPretext: PropTypes.string.isRequired,
+            isSelection: PropTypes.bool,
+            onClick: PropTypes.func
         };
     }
 

webapp/components/suggestion/suggestion_box.jsx

@@ -10,6 +10,8 @@ import AutosizeTextarea from 'components/autosize_textarea.jsx';
 
 const KeyCodes = Constants.KeyCodes;
 
+import PropTypes from 'prop-types';
+
 import React from 'react';
 
 export default class SuggestionBox extends React.Component {
@@ -284,16 +286,16 @@ SuggestionBox.defaultProps = {
 };
 
 SuggestionBox.propTypes = {
-    listComponent: React.PropTypes.func.isRequired,
-    type: React.PropTypes.oneOf(['input', 'textarea', 'search']).isRequired,
-    value: React.PropTypes.string.isRequired,
-    providers: React.PropTypes.arrayOf(React.PropTypes.object),
-    listStyle: React.PropTypes.string,
-    renderDividers: React.PropTypes.bool,
+    listComponent: PropTypes.func.isRequired,
+    type: PropTypes.oneOf(['input', 'textarea', 'search']).isRequired,
+    value: PropTypes.string.isRequired,
+    providers: PropTypes.arrayOf(PropTypes.object),
+    listStyle: PropTypes.string,
+    renderDividers: PropTypes.bool,
 
     // explicitly name any input event handlers we override and need to manually call
-    onBlur: React.PropTypes.func,
-    onChange: React.PropTypes.func,
-    onKeyDown: React.PropTypes.func,
-    onItemSelected: React.PropTypes.func
+    onBlur: PropTypes.func,
+    onChange: PropTypes.func,
+    onKeyDown: PropTypes.func,
+    onItemSelected: PropTypes.func
 };

webapp/components/suggestion/suggestion_list.jsx

@@ -7,13 +7,15 @@ import * as GlobalActions from 'actions/global_actions.jsx';
 import SuggestionStore from 'stores/suggestion_store.jsx';
 import {FormattedMessage} from 'react-intl';
 
+import PropTypes from 'prop-types';
+
 import React from 'react';
 
 export default class SuggestionList extends React.Component {
     static propTypes = {
-        suggestionId: React.PropTypes.string.isRequired,
-        location: React.PropTypes.string,
-        renderDividers: React.PropTypes.bool
+        suggestionId: PropTypes.string.isRequired,
+        location: PropTypes.string,
+        renderDividers: PropTypes.bool
     };
 
     static defaultProps = {