fix(web): handle latest version

[sripwoud]

See #108 (review)

Right now we display a "latest" option in the select input.
However https://registry.npmjs.org does not provide a direct download url for the latest version.

Different way to solve it:

1. Fetch the latest explicit version value

    curl -s https://registry.npmjs.org/@zk-kit/semaphore-artifacts | jq '.["dist-tags"]'
    {
      "latest": "4.0.0-beta.11"
    }
   

2. Do some sorting off line client side with e.g semver.
   Maybe we should not show a 'latest' option at all and simply sort versions in descending order?