docs: specify version in CDN URLs

[hyunbinseo]

Both CDN supports semver in the URL.

Specifying v1 is advised to avoid unexpected breaking changes.

---

use a version range instead of a specific version

https://cdn.jsdelivr.net/npm/[email protected]/dist/jquery.min.js
https://cdn.jsdelivr.net/npm/jquery@3/dist/jquery.min.js

omit the version completely to get the latest one. you should NOT use this in production

https://cdn.jsdelivr.net/npm/jquery/dist/jquery.min.js

You may also use a semver range or a tag instead of a fixed version number, or omit the version/tag entirely to use the latest tag.

https://unpkg.com/react@^16/umd/react.production.min.js