2.12.904 (2024-12-22)

• Fixed an issue when trying to force load Websocket over HTTP/2 or HTTP/3.
• Ensured WebSocket via HTTP/2 with improved CI pipeline featuring haproxy as the reverse proxy.
• Fixed RuntimeError when forcing HTTP/3 by disabling both HTTP/1, and HTTP/2 and the remote is unable to negotiate HTTP/3.
  This issue occurred because of our automatic downgrade procedure introduced in our 2.10.x series. The downgrade ends in panic
  due to unavailable lower protocols. This only improve the UX by not downgrading and letting the original error out.
  See Mypy complains about the type hint for quic_cache_layer.add_domain. niquests#189 for original user report.
• Fixed negotiated extensions for WebSocket being ignored (e.g. per-deflate message).
• Backported HTTPResponse.shutdown() and nullified it. The fix they attempt to ship only concern
  them, we are already safe (based on issue reproduction). See trying to close a response hangs if a blocking read is happening on another thread urllib3/urllib3#2868
• Backported proxy_is_tunneling property to HTTPConnection and HTTPSConnection.
  See Add HTTPSConnection.proxy_is_tunneling urllib3/urllib3#3459
• Backported HTTPSConnection.is_verified to False when using a forwarding proxy.
  See ensure HTTPSconnection.is_verified is set properly urllib3/urllib3#3283
• Backported pickling support to NewConnectionError and NameResolutionError.
  See Added pickling support to NewConnectionError and NameResolutionError urllib3/urllib3#3480