Upgrade github.com/pion/dtls from v2.2.6 to v3.1.1 to fix nonce reuse
vulnerability in AES-GCM ciphers (GHSA-9f3f-wv7r-qc8r). Migrate from
deprecated Config-struct API to ListenWithOptions/ClientWithOptions
options-based API.
v2 Config fields mapped to v3 functional options:
- Certificates, InsecureSkipVerify, ExtendedMasterSecret, ServerName,
RootCAs, ClientCAs, ClientAuth, FlightInterval, MTU
ConnectContextMaker removed — no longer exists in v3; explicit
HandshakeContext(ctx) on *Conn is the replacement for timeout control.
ginuerzh