COPYING file

Could you please change the COPYING file with gnu.org's updated GPL-2 license [1]. Because the current file cause rpmlint incorrect-fsf-address error [2], thank you.

1 : https://www.gnu.org/licenses/old-licenses/gpl-2.0.txt

2 : https://fedoraproject.org/wiki/Common_Rpmlint_issues#incorrect-fsf-address