v0.10.3

Dependency release: quic 2.0.3 and hackney 4.8.4, with the HTTP/3 fixes
they call for.

Changed

• Bump quic 1.8.2 -> 2.0.3, webtransport 0.4.5 -> 0.4.7, h2
  0.12.0 -> 0.12.3 and hackney 4.7.4 -> 4.8.4. hackney 4.8 is what
  pulls quic 2.0 in. For livery's own code nothing changes; if your
  handlers talk to quic_h3 directly, a connection close now always
  arrives as {quic_h3, Conn, {closed, Reason}}.
• The outbound client reports a response body cut short by the server
  closing as {error, {closed, Partial}} (buffered) or {error, closed}
  (streamed), where it used to return the short body as a success.
• Test and check profiles: barrel_mcp 4.1.1, barrel_a2a 0.2.3.

Fixed

• On HTTP/3, a request body over max_body no longer fires the
  handler's on_disconnect callbacks. quic 2.0 reports the reset livery
  sends back to the stream, and the translator took it for a client
  disconnect.
• On HTTP/3, a response sent faster than the connection drains is no
  longer cut. quic refuses a send while its connection send queue is
  full ({error, send_queue_full}, nothing written); livery passed that
  up, so a streamed body silently lost the refused chunk and a full body
  left the stream open. The adapter now waits for the queue to drain,
  sending bodies in 64 KiB pieces, and resets the stream if it is still
  full after 30 seconds ({error, send_timeout}). WebSocket sends over
  HTTP/3 wait the same way.
• A response that fails part way (any emit error other than a closed
  peer) now resets the stream instead of leaving it open.
• on_disconnect callbacks no longer run when livery resets the stream
  itself, for example when a file response cannot be read. HTTP/1.1
  always ran them and HTTP/3 sometimes did; HTTP/2 never did.