build: Use gnome.post_install() function
Introduced in Meson 0.57.0, it simplifies the code a bit: https://mesonbuild.com/Gnome-module.html#gnomepost_install
Icons are not installed so no need to regenerate the icon cache.
Introduced in Meson 0.57.0, it simplifies the code a bit: https://mesonbuild.com/Gnome-module.html#gnomepost_install
Icons are not installed so no need to regenerate the icon cache.