[Development] Raising minimum CMake version to 3.16 for Qt6

[Thiago Macieira]

On Tuesday, 4 May 2021 21:51:36 PDT EXT Craig Scott wrote:
> Given that we haven’t received any reports about this from user projects in
> the year since the code added this constraint, and that we expect to rely
> more on the metatypes going forward rather than less, the CMake Ports team
> proposes to raise the minimum CMake version for user projects to CMake
> 3.16. From what we can tell, the original target of 3.14 was likely based
> on the CMake versions available in major Linux distributions at the time,
> but 3.16 or later now seems to be widely enough available (Ubuntu 20.04 is
> the main blocker for being able to go any higher than 3.16).

3.16.0 was tagged on Nov 2019, which is a little too close for comfort. For 
comparison, we require GCC 8, which was released in May 2018.

However, given that no one has apparently complained and that upgrading cmake 
is far easier than the compiler, I have no objections.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel DPG Cloud Engineering