Copyright for golang-etcd source package in Focal

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: go-etcd
Source: https://github.com/coreos/go-etcd

Files: *
Copyright: 2013-2014 CoreOS Inc.
License: Apache-2.0

Files: debian/*
Copyright: 2014 Jelmer Vernooij 
License: Apache-2.0

License: Apache-2.0
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 .
   http://www.apache.org/licenses/LICENSE-2.0
 .
 On Debian systems, the complete text of the Apache 2.0 
 License can be found in `/usr/share/common-licenses/Apache-2.0`.