Add Passkeys for ASP.NET

Closes #386

Author: timcappalli

content/docs/tools-libraries/libraries.md

@@ -81,6 +81,7 @@ The ["Awesome WebAuthn"](https://github.com/herrjemand/awesome-webauthn) GitHub
 ### .NET
 
 - [FIDO2 .NET Library](https://fido2-net-lib.passwordless.dev/) (Anders Åberg, Alex Seigler)
+- [Passkeys for ASP.NET](https://www.identityserver.com/products/fido2-for-aspnet) (IdentityServer.com)
 
 ### Go