Proposal to update default Windows build chain to Visual Studio 2019

[Stephan Bergmann]

On 13/02/2020 11:12, Noel Grandin wrote:
> I propose that we updated our Windows builders to use VS2019 and make 
> that our new preferred baseline.

Any specific version of VS 2019?  Especially regarding C++ conformance, 
they typically ship improvements in minor updates (though it doesn't 
look like there would be any C++17 feature that would only come with a 
specific VS 2019 minor update, see 
<https://en.cppreference.com/w/cpp/compiler_support>, but at least for 
experimental C++2a support it does make a difference).

If there a no good reasons to the contrary, I would suggest that if we 
upgrade the baseline to VS 2019, we upgrade it to the latest VS 2019 
16.4 (aka 19.24, see 
<https://en.wikipedia.org/wiki/Microsoft_Visual_C%2B%2B#Internal_version_numbering>).