Increasing KF5 cmake requirement to 3.6?

[Wolfgang Bauer]

> -----Original Message-----
> I'm going to suggest it to increase it to 3.6, it would still most
probably be a lie
> since i don't think any of use uses such an old (2 years version) either

We currently do still build the latest KDE Frameworks, Plasma, and
Applications on/for openSUSE Leap 42.3 (plus latest Qt5) with cmake 3.5.2.
 
Only problem so far: discover started to use a new feature of cmake 3.6 in
the latest (bugfix) version, namely the IMPORTED_TARGET option to
pkg_checkmodule(), so the flatpak and fwupd backends are not built anymore
with cmake 3.5.2. (cmake says "No package 'IMPORTED_TARGET' found")
https://cgit.kde.org/discover.git/commit/?h=Plasma/5.14&id=d9ccf1d41fc3265ae
e9e01eebbc090b163fefe07
https://cgit.kde.org/discover.git/commit/?h=Plasma/5.14&id=2fe3d58fc652fc995
7f063cbbd0722dc1cf45730
(we couldn't build the fwupd backend anyway though because fwupd is too old)

Kind Regards,
Wolfgang