Currently if the data isn't able to be fetched it fails and kills the whole build:

Error fetching https://api.microlink.io/?url=https://trib.al/5t27Gcr. Message: Bad response for https://api.microlink.io/?url=https://trib.al/5t27Gcr (429): Too Many Requests
Failing gracefully with an expired cache entry.
[11ty] Problem writing Eleventy templates: (more in DEBUG output)
[11ty] 1. Having trouble rendering njk template ./src/garden/CSS Nesting.md (via TemplateContentRenderError)
[11ty] 2. (./src/garden/CSS Nesting.md)
[11ty]   EleventyShortcodeError: Error with Nunjucks shortcode `unfurl` (via Template render error)
[11ty] 3. Bad response for https://api.microlink.io/?url=https://developer.chrome.com/blog/help-css-nesting/ (429): Too Many Requests (via Template render error)
[11ty]
[11ty] Original error stack trace: Error: Bad response for https://api.microlink.io/?url=https://developer.chrome.com/blog/help-css-nesting/ (429): Too Many Requests
[11ty]     at RemoteAssetCache.fetch (/Users/ellyloel/git/ellyloel.com/node_modules/@11ty/eleventy-cache-assets/src/RemoteAssetCache.js:55:11)
[11ty]     at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
[11ty]     at async run (/Users/ellyloel/git/ellyloel.com/node_modules/p-queue/dist/index.js:163:29)
[11ty] Copied 65 files / Wrote 0 files in 96.66 seconds (v2.0.0-canary.18)
error Command failed with exit code 1.

It might be nice to fail gracefully and return the link to be displayed instead.

try {
  const metadata = await Cache(`https://api.microlink.io/?url=${link}`, {
    duration: "1m",
    type: "json",
  });
 
  if (options.template) {
    return options.template(metadata.data);
  }
  return template(metadata.data);
} catch(e) {
  console.error(e);
  return link;
}

Also, on another note, it could be good to make an option for the cache duration, and switch from Eleventy cache assets to Eleventy fetch.

const metadata = await EleventyFetch(`https://api.microlink.io/?url=${link}`, {
  duration: options?.duration || "1m",
  type: "json",
});

• Prevent errors in builds if the API failed to return data, thanks @EllyLoel! (Fixes #1)
• Clean up template code so it's easier to read overall
• Clean up docs and lean on external docs for more accuracy
• Remove lock file to prevent getting annoying error reports via email