x11-themes/xcursor-themes: Update to 1.0.6

Update xcursor-themes to 1.0.6. This adds some symlinks to the whiteglass
cursor theme, that gnome-shell expects. [1]
Add NO_ARCH since this doesn't install any architecture specific files. [2]
Remove unneded dependency on xorgproto. [2]

Changelog:
https://lists.x.org/archives/xorg/2019-February/059607.html

PR: 235936 [1]
Submitted by: Samy Mahmoudi [1], zeising [2]
Sponsored by: B3 Init (zeising)