Upgrade D3D12 Agility SDK to 1.619.1

[MarijnS95]

Depends on #2170

https://devblogs.microsoft.com/directx/shader-model-6-9-retail-and-more/

[MarijnS95]

For those interested, as usual I've also regenerated the bindings for the 719 preview here:

https://github.com/Traverse-Research/win32metadata/compare/agility-1.719
https://github.com/Traverse-Research/windows-rs/compare/windows-66-agility-sdk-1.719

[MarijnS95]

@riverar reverse-ping, I'd love to just get #2170 and this in. Continuously rebasing it only to fix conflicts in the change file and undoing approvals that way isn't super productive.

[jevansaks]

I believe I resolved the issue with the pipeline (needed to save the new packages to the feed). Do we need to get #2170 in first?

[jevansaks]

@MarijnS95 I'm going to merge this change in. If you still want the other PR merged. This PR looks comprehensive so just close the other one if it's not needed anymore.

[MarijnS95]

Thanks @jevansaks. This PR is purely based on top of #2170 so nothing is lost in the end. We just don't have a separate commit in history upgrading from 1.618.2 to 1.618.5 ahead of 1.619.1, but that is unlikely to be useful to anyone.