Update flatpack

Bump version to 1.4.1; Update Changelog

Fix typo

Minor cleanup (#188)

* Use license file from gnu.org

This fixes a strange typo in the license file, as well as upgrades links
to https and fixes one redirect.

Downloaded from:
https://www.gnu.org/licenses/gpl-3.0.txt

* Fix shellcheck warnings

Co-authored-by: Your Name <you@example.com>

1.3.12 release;

Update translations;

Bump version to 1.3.10;

Bump version to 1.3.9

Update ChangeLog

 Bind Plus and Minus keys for Config tab for +\- zoom respectively; A…

…llow to change Config and Program Icon sizes independently [BUG-112];