Update libadwaita colors

[wroyca]

The Libadwaita color scheme has been updated, resulting in most of the colors being inaccurate
e.g. with tabs:

before

after

[piousdeer]

Thanks for the alert. I'll address this in a major version release along with all the other currently open issues. A lot of unfinished work has been lying stalled in my local branch, but I'll be able to continue in a few days.