Copyright for golang-pb source package in Bionic

Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/

Files: debian/*
Copyright: Copyright (C) 2013 Canonical, Ltd.
License: BSD-3-Clause

Files: *
Copyright: Copyright (c) 2012, Sergey Cherepanov 
License: BSD-3-Clause

License: BSD-3-Clause
 All rights reserved.
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 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions 
 are met:
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 * Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
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  * Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in
    the documentation and/or other materials provided with the distribution.
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 * Neither the name of the author nor the names of its contributors may 
   be used to endorse or promote products derived from this software 
   without specific prior written permission.
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 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.