Hybrid transport runtime errors fixes (#127)

## 1. Tungstenite now requiring selecting a crypto provider

A panic at runtime when attempting to establish a secure WebSocket
connection:

```
DEBUG tokio_tungstenite::tls::encryption::rustls: Added 148/148 native root certificates (ignored 0)    

thread 'main' panicked at /home/afresta/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rustls-0.23.27/src/crypto/mod.rs:249:14:
no process-level CryptoProvider available -- call CryptoProvider::install_default() before this point
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```

For more details, see:
* snapview/tokio-tungstenite#336
* snapview/tokio-tungstenite#353

This is now fixed by explicitly selecting `rustls` as the `tungstenite`
TLS backend, as recommended in `tokio-tungstenite`.

## 2. Hybrid initial GetInfo deserialization fails

An error deserializing the caBLE initial message containing the GetInfo
response:

```
DEBUG libwebauthn::transport::cable::tunnel: Responding to GetInfo request with cached response
ERROR webauthn_make_credential{dev=CableChannel}:ctap2_get_info: libwebauthn::proto::ctap2::protocol: Failed to parse Ctap2GetInfoResponse from CBOR-data provided by the device. Parsing error: SerdeCbor(ErrorImpl { code: Message("invalid type: byte array, expected Ctap2GetInfoResponse"), offset: 0 })

thread 'main' panicked at libwebauthn/examples/webauthn_cable.rs:139:10:
called `Result::unwrap()` on an `Err` value: Platform(InvalidDeviceResponse)
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```

This was accidentally introduced in #110:
https://github.com/linux-credentials/libwebauthn/pull/110/files#diff-d061af4011a3c577c5c2dbef3b1933b0e8c8a9ebc0bf70a0ebc3358e890ed725R587

Fixed by using the appropriate serialization method.

Author: AlfioEmanueleFresta

Cargo.lock

@@ -60,6 +60,7 @@ tungstenite = { version = "0.26.2" }
 tokio-tungstenite = { version = "0.26", features = [
     "rustls-tls-native-roots",
 ] }
+rustls = { version = "0.23.27", features = ["ring"] }
 tokio-stream = "0.1"
 snow = { version = "0.10.0-beta.1", features = ["use-p256"] }
 ctap-types = { version = "0.4.0" }