Bump (c) year

(cherry picked from commit 1752698)

Author: michaelklishin

deps/rabbitmq_cli/lib/rabbitmq/cli/ctl/commands/close_all_user_connections_command.ex

@@ -2,7 +2,7 @@
 ## License, v. 2.0. If a copy of the MPL was not distributed with this
 ## file, You can obtain one at https://mozilla.org/MPL/2.0/.
 ##
-## Copyright (c) 2007-2020 VMware, Inc. or its affiliates.  All rights reserved.
+## Copyright (c) 2007-2021 VMware, Inc. or its affiliates.  All rights reserved.
 
 defmodule RabbitMQ.CLI.Ctl.Commands.CloseAllUserConnectionsCommand do
   alias RabbitMQ.CLI.Core.DocGuide