Version 3.0 for Plasma 6

Added Gammastep as optional and default backend.

Due to Redshift being long abandoned and after upgrading to Ubuntu 24.04 not working from applet (from plasmoidviewer it works) for reasons unknown to me, I decided to add Gammastep as optional and set by default backend.

Don't forget to switch off Gammastep's autostart:

rm ~/.config/autostart/gammastep-indicator.desktop
systemctl --user disable --now gammastep-indicator
systemctl --user mask gammastep-indicator
systemctl --user disable --now gammastep
systemctl --user mask gammastep

Full Changelog: 2.2...3.0

Version 2.2 for Plasma 6

It is last version for Redshift only.

Full Changelog: 2.1...2.2

Version 2.1 for Plasma 6

Initial release.