The new upstream is https://github.com/swaywm/swaybg
This commit also refactors our use of gdk-pixbuf a bit, since the only
remaining reverse dependency is swaybar tray support.
* Updated the french readme
Removed the image at the start of the readme.
Removed the mention of bounties.
Updated the dependencies.
Removed a few lines that were not present in the english readme anymore.
* Fix errors.
Fixed capitalisation.
Changed "root" to italics.
to 0.12.1. This is needed because the development
version breaks the existing API of json_object_array_length()
by moving the return from int to size_t.
This would fix #1355
