Python 3.14 support

[Houbein]

currently there is no Python 3.14 wheel.
Pip can compile the source code on 3.14, but explicit 3.14 support with a dedicated wheel would be better.

[Nepitwin]

Actually appveyor does not include python 3.14 as pre installed software

https://www.appveyor.com/docs/windows-images-software/#python

So actually i have to look how to adjust the appveyor.yml with Python 3.14 build or to wait until appveyor support this as pre installed version