chore: Add a schema compatibility check to the CI for the OH CLI

[bramj]

A first attempt at trying to catch the "Breaking changes detected" warning in the CLI ahead of a new release.

This PR adds a check on the schema compatibility of the openhexa CLI with two checks:

1. A check on a release-please PR to check schema compatibility with prod
2. A daily check (every morning at 9) to check the latest release with the production server. If there's a schema mismatch (which would mean a warning when using the SDK), the cron sends a Slack notification.

What do you think of this general approach?

[yolanfery]

[For further improvement] We could automate this also by Opening a PR with the new schema and codegen ran

[yolanfery]

TLDR; I think it is great and sufficient like this 😊

My opinion is that, in theory, we need a check each time the app is released to see if the latest SDK is compatible so that we ensure each app version has a compatible sdk version. So a GitHub action on release please of openhexa-app

But in practice we spent days between an app release and actually releasing it to prod (testing in demo etc). So it means we could have SDK version that are unnecessarily published in advance, leading to confusion among users that need to use an older version of the SDK.

So I think you changed my mind and I think this is actually great like that 👌
(Maybe we could even remove the release please part [I feel it's not that useful] and only keeping the cron for simplicity, but I am not against keeping it)

To go further (at some point if we want):

• We can consider automating the schema/codegen update by opening a PR and assigning one of us
• I think it would be valuable to have the same mechanism discussed for docker images : a tag (main) to test in demo before publishing a new release. In Pypi I think we need to rely on .dev version numbers (no string tags)