chore(deps): update dependency @types/node to v16 (#5170)

* Update Node types to 16

* Update Express core types

Fixes a number of conflicts it has with Node 16.

* Fix websocket router types

It seems req was `any` before so now we have to handle the types.  Also
it seems the socket is of type `stream.Duplex`, not `net.Socket`.

The ws types had to be updated to support the new type.

Unfortunately Code still uses the old type so cast for now.

In the web socket router just use a cast for the extra properties we
add.  We could add the types to the Express namespace but I am not sure
we really want these commonly accessible so keep with the casts for now.
Likely we should use Express's `locals` or something instead.

* Add missing return

Not sure why it only just now started complaining though.

Co-authored-by: Asher <ash@coder.com>

typings/pluginapi.d.ts

@@ -5,7 +5,7 @@ import { field, Level, Logger } from "@coder/logger"
 import * as express from "express"
 import * as expressCore from "express-serve-static-core"
 import ProxyServer from "http-proxy"
-import * as net from "net"
+import * as stream from "stream"
 import Websocket from "ws"
 
 /**
@@ -97,7 +97,7 @@ export declare class HttpError extends Error {
 }
 
 export interface WebsocketRequest extends express.Request {
-  ws: net.Socket
+  ws: stream.Duplex
   head: Buffer
 }