Replace GitHub Action Caches with NuGet Package Caches

[LegalizeAdulthood]

Since the x-gha GitHub Action Cache method for VCPKG_BINARY_SOURCES has been removed and it is suggested you use NuGet package caching instead, I wrote up a gist on what I learned while converting one of my projects:

Using NuGet Package Caching with VcPkg and GitHub Actions

Perhaps this will be of use to others.

[vicroms]

Hi @LegalizeAdulthood

If you're willing, please open a PR in our documentation repository to improve the existing binary caching with GitHub Packages article.