RFC: Switching to min Qt version 5.14 for KF on December 14th

[Friedrich W. H. Kossebau]

Hi,

you might have seen I asked* whether anyone knows a real world requirement to 
stick with Qt 5.13 as new current minimum required Qt version for current KF 
releases. So far no-one had to report a reason to support Qt >= 5.13 instead 
of only Qt >= 5.14 now.
* E.g. https://mail.kde.org/pipermail/distributions/2020-December/000894.html

So hereby I propose to switch for KF 5.78 to Qt 5.14 as minimum version, and 
change the KF dependencies policy text* to this:
* https://community.kde.org/Frameworks/Policies#Frameworks_Qt_requirements 

"
With Qt6 this changes a little bit again. We interpolate "as if" more Qt 5 
versions would be released. Then adapt to actual real world usage of a given 
Qt version:
* Qt 5.13 will be the minimum required version 6 months after Qt 5.15, i.e. on 
26 Nov 2020
* Qt 5.14 would be the minimum required version 12 months after Qt 5.15, i.e. 
on 26 May 2021. With no-one known to stick with Qt 5.13, the date is moved to 
earlier mid-December 2020.
* Qt 5.15 LTS will be the minimum required version 18 months after its 
release, i.e. on 26 Nov 2021
"

from previous

"
With Qt6 this changes a little bit again. We interpolate "as if" more Qt 5 
versions would be released: 
* Qt 5.13 will be the minimum required version 6 months after Qt 5.15, i.e. on 
26 Nov 2020
* Qt 5.14 will be the minimum required version 12 months after Qt 5.15, i.e. 
on 26 May 2021
* Qt 5.15 LTS will be the minimum required version 18 months after its 
release, i.e. on 26 Nov 2021
"

I also propose that if no objections pop up until Monday, December 14th, CET 
Noon, we then go that day and update the policy and have our dependency 
bumping service people execute the bump to Qt 5.14.

Your comments, please :)

Cheers
Friedrich