Update NASM and VapourSynth in windows-build.yml

[Uranite]

And remove unnecessary Python setup

[shssoichiro]

lgtm, thanks!

[FreezyLemon]

IIRC this was necessary because the default python version on the runner was not compatible with the chosen VS version. It's likely this changed (which is why it works now), but note that this could break down the line when the github action runners are updated.

[Uranite]

IIRC this was necessary because the default python version on the runner was not compatible with the chosen VS version. It's likely this changed (which is why it works now), but note that this could break down the line when the github action runners are updated.

Hmm, that cant be it, since VapourSynth is portable and you don't need python for portable vapoursynth