Cope with the KeyBindingMode move of 3.7.5

Its location changed from Main to Shell and its case changed from
KeybindingMode to KeyBindingMode.
Work around the new frame sync of mutter 3.7.90

I did not investigate the issue fully, but it covers it for the time
being, as this is really bothering when you extensively use the terminal.

Also, bump the supported gnome-shell versions.