Changing SpinPunch to Mattermost in copyright

web/react/components/unread_channel_indicator.jsx

@@ -1,4 +1,4 @@
-// Copyright (c) 2015 Spinpunch, Inc. All Rights Reserved.
+// Copyright (c) 2015 Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
 // Indicator for the left sidebar which indicate if there's unread posts in a channel that is not shown