feat(rumqttc): update async-tungstenite to 0.32, remove ws_stream_tungstenite

[michelhe]

async-tungstenite 0.32 includes a built-in bytes module with ByteReader and ByteWriter types that provide tokio::io::AsyncRead/AsyncWrite over WebSocket streams. This makes the ws_stream_tungstenite crate redundant, and that crate pins async-tungstenite ^0.29, blocking the upgrade.

Changes:

• Update async-tungstenite from 0.29 to 0.32
• Remove ws_stream_tungstenite dependency
• Add a custom WsStream adapter in websockets.rs that wraps async-tungstenite's ByteReader/ByteWriter to provide tokio IO traits
• Add futures-io and pin-project-lite as optional websocket dependencies
• Update v4 and v5 eventloop imports accordingly

Type of change

• Miscellaneous (related to maintenance)

Checklist:

• Formatted with cargo fmt
• Make an entry to CHANGELOG.md if it's relevant to the users of the library. If it's not relevant mention why. - Not relevant, this is an internal implementation detail.

[thehouseisonfire]

pin_project! is actually better than my current approach if the downstream transport is !Unpin, though from what I can tell most today are Unpin (like tokio::net::TcpStream and quinn's RecvStream/SendStream).

Would you (or anyone reading) happen to have a reference or use case for supporting !Unpin?

[thehouseisonfire]

Also noting that the dependency tree does include proc-macro2 somewhat extensively, so pin-project could also be used per pin-project-lite's maintainer.