Update required KF5 and Kirigami dependencies

Summary:
Unfortunately Kirigami has an unchanged internal version of 5.22.0,
thus cmake can't possibly detect it. But as it doesn't affect the
build anyway, it's IMO an improvenment for the human reader or
packager to determine which version is required.

Reviewers: #plasma, mart

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D5807