## Feature
- [x] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [x] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Changes
Added in on-demand revalidation for Contentful example. Specifically, added the revalidate api path, a new environment variable which will contain the secret, and some additions to the README.
Co-authored-by: JJ Kasper <22380829+ijjk@users.noreply.github.com>
[ch2502]
- Added new import flow to every CMS example, using the deploy button, and removed `vercel.json`
- Replaced `dotenv` with the new env support in outdated examples
