feat: support MutualTLS.

[MikuSugar]

Provided mutual authentication support。

  //Used for bidirectional authentication
    pub fn with_mutual_tls_validation(
        mut self,
        client_cert: Option<impl AsRef<Path>>,
        ssl_cert: impl AsRef<Path>,
        ssl_key: impl AsRef<Path>,
    ) -> Self {
        self.tls_config =
            ConnectionTLSConfig::MutualTLS(MutualTLS::new(client_cert, ssl_cert, ssl_key));
        self
    }

#247

[madchicken]

Thanks for this addition!

[knutwalker]

Nice, thanks for adding this!