Copyright for indi-ffmv source package in Oracular

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: indi-ffmv
Source: https://github.com/indilib/indi-3rdparty

Files: *
Copyright: 2013 Ben Gilsrud
License: LGPL-2.1+

Files: debian/*
Copyright: 2021-2023 Thorsten Alteholz 
           2018 Jasem Mutlaq 
License: LGPL-2.1+

License: LGPL-2.1+
 On Debian based system the LGPL-2.1 can be found in /usr/share/common-licenses/LGPL-2.1