Replace React.PropTypes with usage of the prop-types package

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/views/dialogs/BugReportDialog.js

@@ -1,6 +1,7 @@
 /*
 Copyright 2017 OpenMarket Ltd
 Copyright 2018 New Vector Ltd
+Copyright 2019 Michael Telatynski <7t3chguy@gmail.com>
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -16,6 +17,7 @@ limitations under the License.
 */
 
 import React from 'react';
+import PropTypes from 'prop-types';
 import sdk from '../../../index';
 import SdkConfig from '../../../SdkConfig';
 import Modal from '../../../Modal';
@@ -200,5 +202,5 @@ export default class BugReportDialog extends React.Component {
 }
 
 BugReportDialog.propTypes = {
-    onFinished: React.PropTypes.func.isRequired,
+    onFinished: PropTypes.func.isRequired,
 };

src/components/views/dialogs/ChangelogDialog.js

@@ -1,5 +1,6 @@
 /*
  Copyright 2016 Aviral Dasgupta
+Copyright 2019 Michael Telatynski <7t3chguy@gmail.com>
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -15,6 +16,7 @@
  */
 
 import React from 'react';
+import PropTypes from 'prop-types';
 import sdk from '../../../index';
 import request from 'browser-request';
 import { _t } from '../../../languageHandler';
@@ -99,7 +101,7 @@ export default class ChangelogDialog extends React.Component {
 }
 
 ChangelogDialog.propTypes = {
-    version: React.PropTypes.string.isRequired,
-    newVersion: React.PropTypes.string.isRequired,
-    onFinished: React.PropTypes.func.isRequired,
+    version: PropTypes.string.isRequired,
+    newVersion: PropTypes.string.isRequired,
+    onFinished: PropTypes.func.isRequired,
 };

src/components/views/dialogs/SetPasswordDialog.js

@@ -1,6 +1,7 @@
 /*
 Copyright 2017 Vector Creations Ltd
 Copyright 2018 New Vector Ltd
+Copyright 2019 Michael Telatynski <7t3chguy@gmail.com>
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -16,6 +17,7 @@ limitations under the License.
 */
 
 import React from 'react';
+import PropTypes from 'prop-types';
 import sdk from '../../../index';
 import { _t } from '../../../languageHandler';
 import Modal from '../../../Modal';
@@ -63,7 +65,7 @@ const WarmFuzzy = function(props) {
 export default React.createClass({
     displayName: 'SetPasswordDialog',
     propTypes: {
-        onFinished: React.PropTypes.func.isRequired,
+        onFinished: PropTypes.func.isRequired,
     },
 
     getInitialState: function() {