Vapor: 4.42.0 Release

This patch was authored by @wacumov and released by @0xTim.

Adds a way to manually upgrade an incoming request to WebSocket (https://github.com/vapor/vapor/issues/2235).

app.get("socket") { req in
    // Check things from the request.
    return req.webSocket { req, ws in
        // Handle WebSocket lifecycle here
    }
}