PLT-5860 Updated copyright date (#6058)

* PLT-5860 Updated copyright date in about modal

* PLT-5860 Updated copyright notice in JSX files

* PLT-5860 Updated copyright notice in go files

* Fixed misc copyright dates

* Fixed component snapshots

webapp/components/analytics/doughnut_chart.jsx

@@ -1,4 +1,4 @@
-// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
 import {FormattedMessage} from 'react-intl';

webapp/components/analytics/line_chart.jsx

@@ -1,4 +1,4 @@
-// Copyright (c) 2015 Mattermost, Inc. All Rights Reserved.
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
 import {FormattedMessage} from 'react-intl';

webapp/components/analytics/statistic_count.jsx

@@ -1,4 +1,4 @@
-// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
 import {FormattedMessage} from 'react-intl';

webapp/components/analytics/system_analytics.jsx

@@ -1,4 +1,4 @@
-// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
 import LineChart from './line_chart.jsx';

webapp/components/analytics/table_chart.jsx

@@ -1,4 +1,4 @@
-// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
 import Constants from 'utils/constants.jsx';

webapp/components/analytics/team_analytics.jsx

@@ -1,4 +1,4 @@
-// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
 import React from 'react';