Update libraries.md

Add Swift library

Author: 0xTim

content/en/docs/tools-libraries/libraries.md

@@ -94,3 +94,7 @@ The ["Awesome WebAuthn"](https://github.com/herrjemand/awesome-webauthn) GitHub
 - [webauthn-ruby](https://github.com/cedarcode/webauthn-ruby) (Cedarcode)
 - [devise-passkeys](https://github.com/ruby-passkeys/devise-passkeys) (Ruby Passkeys, wrapper around `webauthn-ruby`)
 - [warden-webauthn](https://github.com/ruby-passkeys/warden-webauthn) (Ruby Passkeys, wrapper around `webauthn-ruby`)
+
+### Swift
+
+- [Swift WebAuthn](https://github.com/swift-server/swift-webauthn) ([Swift Server Workgroup](https://www.swift.org/sswg/))