releases: Consider using new Releases API instead of Checkpoint

[kmoe]

More research needed.

[radeksimko]

New API is now live and docs are available at https://releases.hashicorp.com/docs/api/v1/

[radeksimko]

I think we could try to move releases package from the static JSON to the API as the first step, without having to make any decisions about Checkpoint yet.

However I'd like to explore the possibility of the API exposing version constraint resolution endpoint, so that we don't have to keep looping over all versions to pick just one.

[jukie]

Hi, has there been any more discussions on how you'd like to implement the API? I'd like to contribute towards some of that work.

[radeksimko]

@jukie Not yet, but we did discuss a potential addition of a new endpoint to the API, ideally prior to the implementation. Specifically one that would allow us to resolve product version based on constraint, i.e. something similar to https://releases.hashicorp.com/docs/api/v1/#operation/getReleaseV1 where one can pass constraint such as <= 1.0 and get the latest matching version.

This would allow us to more easily/efficiently re-implement releases.LatestVersion{}, in particular the Constraints field.

Currently the querying is pretty inefficient in that we have to pull all versions and range over every single one until we find the one that matches the constraints, so having such an endpoint would then be a great motivation to migrate to that API.