Add realeases/next.php endpoint

[renanbr]

This Pull Request is actually a feature request.

The goal is to expose an endpoint that users can use to fetch the upcoming release.

The realeases/next.php returns a JSON response with the next version, for example:

"8.2"

I don't mind if another approach is proposed instead.

[cmb69]

The goal is to expose an endpoint that users can use to fetch the upcoming release.

Hmm, I don't understand the reason for that. https://www.php.net/releases/active.php already lists all current GA releases, while https://qa.php.net/api.php?type=qa-releases&format=json lists all current QA releases.

[renanbr]

Thank you @cmb69 , didn't know the second link. This one solves my problem 🥂