Add copyright.whitelist

Add copyright.whitelist

scan-licenses job reported the below error,

ERROR:
 Blacklisted license entry found: CopyrightEntry(file='win32port/win32helpers/*', license='BSD-4-clause')
 Blacklisted license entry found: CopyrightEntry(file='win32port/win32helpers/getopt_long.c', license='BSD-4-clause')

win32port contains windows specific build files and not part of installable artifacts. So whitelist these files which has incompatible BSD-4-clause license.

Fixes: https://phabricator.apertis.org/T9132