gnucash-docs maint: Add license file to git tracking

[Geert Janssens]

Updated	 via  https://github.com/Gnucash/gnucash-docs/commit/ab60da39 (commit)
	from  https://github.com/Gnucash/gnucash-docs/commit/7c0642f0 (commit)



commit ab60da39de71b488bd533cae20b06dfe0b2ee3d0
Author: Geert Janssens <geert at kobaltwit.be>
Date:   Wed Sep 22 16:19:42 2021 +0200

    Add license file to git tracking
    
    It is an autogenerated file from autotools but it was
    ignored by our current git config. A previous commit
    chose to install the file, but that's difficult if it's
    missing.



Summary of changes:
 .gitignore | 3 +--
 COPYING    | 1 +
 2 files changed, 2 insertions(+), 2 deletions(-)
 create mode 120000 COPYING