Utilize cache

[ForNeVeR]

Hi! I like this project and the whole concept of playground for doing NuGet package development in a "right way" via GitHub.

What's your opinion on using the GitHub Action Cache for NuGet packages used by the project? The cache has pros and cons.

As a maintainer of several projects of variable size I should note that using the cache (if possible) usually reduces build errors that happen due to network failures at the package restore step.

On the other hand, cache requires maintenance on its own, because typical modern projects may easily require several gigabytes of cache to be preserved between builds, and GitHub (to my knowledge) limits the cache size for free repositories to 2 GiB today. And if you exceed this size, then the whole cache experience quickly becomes clunky (slower uploads, slower downloads, cache failures).