chore: update pico css version

Author: edysegura

broadcast-channel/another-page.html

@@ -6,7 +6,7 @@
  <title>HTML5 API - Broadcast Channel API</title>
  <link
  rel="stylesheet"
- href="https://cdn.jsdelivr.net/npm/@picocss/pico@1/css/pico.min.css"
+ href="https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css"
  />
  <script src="another-page.js" type="module" defer></script>
  </head>

broadcast-channel/index.html

@@ -6,7 +6,7 @@
  <title>HTML5 API - Broadcast Channel API</title>
  <link
  rel="stylesheet"
- href="https://cdn.jsdelivr.net/npm/@picocss/pico@1/css/pico.min.css"
+ href="https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css"
  />
  <script src="app.js" type="module" defer></script>
  </head>