4.2.0

Added

• IPv6 for HTTP/3. The family connect option (inet | inet6) is forwarded to QUIC, which resolves DNS and races addresses with Happy Eyeballs (RFC 8305). IPv6 literals such as https://[::1]/ work too.
• 0-RTT and session resumption for HTTP/3. Session tickets are cached per {host, port, transport} and replayed on the next connection; a bodyless one-shot request is then sent as 0-RTT, otherwise the ticket gives a resumed handshake. Controlled by the zero_rtt option, with an explicit session_ticket taking precedence. New hackney_h3 helpers: early_data_accepted/1, get_session_ticket/1, wait_session_ticket/2.

Fixed

• Recover from an expired cross-signed root instead of failing the handshake (e.g. Let's Encrypt's ISRG Root X2 cross-signed by the expired ISRG Root X1), across HTTP/1.1, HTTP/2, HTTP/3 and WebTransport. A genuinely expired leaf or intermediate still fails, and partial chains keep working.
• HTTP/3 connections from the pool now apply ssl_options (cacerts, insecure) that previously did not reach the QUIC layer.
• A pooled connection that stops between checkout and the request call no longer leaks exit:{normal, _} / exit:noproc to the caller; request, body and streaming calls return {error, closed} instead (#861).
• A proxy host given as an atom (e.g. localhost) or a binary is accepted again for the plain, connect and socks5 proxy tuples instead of being silently ignored (#858).

Dependencies

• quic 1.4.5 -> 1.6.3.
• h2 0.6.1 -> 0.8.0.
• webtransport 0.2.6 -> 0.3.1.