Windows support: leverage the support of Named Pipes in gRPC target strings in go-spiffe

[amartinezfayo]

go-spiffe now supports Named Pipes in gRPC target strings, since v2.1.1.
This can simplify the current usage of named pipes in SPIRE through the go-spiffe library.

[github-actions]

This issue is stale because it has been open for 365 days with no activity.

[github-actions]

This issue was closed because it has been inactive for 30 days since being marked as stale.

[azdagron]

Still relevant.