3.23.0

• Add initial support for Gtk4 and libhandy
• Fix dark xfwm4-a11y install path (Issue #307)
• Fix xfwm4-a11y and xfwm4-compact install path (Issue #307)
• Fix: GtkLabel: Backdropped selection color adjusted
• Fix: Backdropped selection: GtkListBoxes weren't grey
• Hotfix: removed background color for non-bg items
• Gtk3: Adjusted selected backdrop fg/bg colors: shades of grey.
• Changes the xfwm4 border colors
• build: refactor meson
• Correct gradients for horizontal scrollbars
• Reduce messagedialog buttonbox size
• Make CSD titlebars slimmer