Dependency caching restore super slow on Windows

[mattjohnsonpint]

https://github.com/getsentry/sentry-dotnet/runs/6327391846?check_suite_focus=true

Time to restore dependencies from cache:

Ubuntu	macOS	Windows
18s	29s	4m 5s

With timings visible, it's clearly the tar operation that is the culprit:

Others appear to be having the same issue. Reported on the thread here: actions/cache#752 (comment)

[mattjohnsonpint]

Going to disable it on Windows for now. Leaving this issue open though, so we can remember to turn it back on when GitHub fixes the underlying issue.

[bitsandfoxes]

Closing this as it got cleaned up along the way somewhere.