Readme added to package

Reference updates, build on .NET 8

Azure Identity update

Merge branch 'main' into fsharp6

# Conflicts:
#	KeyVaultSigning/KeyVaultSigning.fsproj

revert to F# 6

Package updates

- Async to use Task

- Configurable 5 min cache of GetKey
- Added more Tests
- References updated

1.0.2: Verify async added