Merged from the 3.5.x branch.

Fixes #580

Diff: 4.0.5...4.0.6

In order to ease the migration to Socket.IO v3, the Engine.IO server
can now communicate with v3.x clients.

```js
const eioServer = require("engine.io")(httpServer, {
  allowEIO3: true // false by default
});
```

If `allowEIO3` is false, the v3.x clients will now receive an HTTP 400
response ("Unsupported protocol version").

Note: the code of the v3 parser has been imported from [1] and
browser-related dependencies were removed.

[1]: https://github.com/socketio/engine.io-parser/tree/2.2.1

Related:

- socketio/engine.io-protocol#35
- socketio/socket.io-protocol#21

Diff: 4.0.6...4.1.0

There was two issues with this behavior:

- v3 clients (with allowEIO3: true) were also receiving a "ping" after
a successful upgrade, which is incorrect (in v3, it's the client that
sends the "ping", and the server answers with a "pong")

- the ping timer is not reset after upgrade on the client-side, so an
upgrade which took longer than the `pingTimeout` duration could lead to
a "ping timeout" error on the client-side

I think the latter issue is present since the initial implementation.

Related: socketio/socket.io-client-swift#1309 (comment)

Reference: https://docs.github.com/en/actions/managing-workflow-runs/adding-a-workflow-status-badge#using-the-branch-parameter

Diff: 4.1.0...4.1.1

**IMPORTANT SECURITY FIX**

A malicious client could send a specially crafted HTTP request,
triggering an uncaught exception and killing the Node.js process:

> RangeError: Invalid WebSocket frame: RSV2 and RSV3 must be clear
>   at Receiver.getInfo (/.../node_modules/ws/lib/receiver.js:176:14)
>   at Receiver.startLoop (/.../node_modules/ws/lib/receiver.js:136:22)
>   at Receiver._write (/.../node_modules/ws/lib/receiver.js:83:10)
>   at writeOrBuffer (internal/streams/writable.js:358:12)

This bug was introduced by [1], included in `[email protected]`, so
previous releases are not impacted.

[1]: f3c291f

Thanks to Marcus Wejderot from Mevisio for the responsible disclosure.

Backported from master: c0e194d

Diff: 4.1.1...4.1.2