Plasma 5.8 will need Kirigami 1.1

[Jonathan Riddell]

Some final changes to Kirigami and Discover (and some lax release
management) mean Plasma 5.8 will need the newly released Kirigami 1.1.

https://www.kde.org/announcements/kirigami-1.1.php
https://techbase.kde.org/Kirigami

Jonathan