gtk+ 3.22.8 release.

Wayland:

• Avoid overlap between Alt and Meta

Bugs fixed:

• 358970 gtk_scale_set_digits does not cause value to be rounded if draw-value...
• 765161 on win32 maximized window position wrong when windows toolbar is on l...
• 765410 Scrollbar does not update since 3.20
• 770112 The documented <alt>left shortcut doesn’t work on Wayland
• 773686 Software when launched shows in dash with wrong icon, name and menu
• 775732 mir: clipboard support missing
• 775864 getting-started: typo tie->the
• 777527 GDK W32: Invisible drop-down menus in GTK apps when working via RDP
• 777547 Notebook arrow icon wrong color after closing final tab