Improve compatibility matrix testing

[jsoriano]

Currently, packages in this repository have limited testing coverage with different versions of the stack:

• On PRs, they are tested with the last supported version according to the kibana.version constraint. This is done to ensure that backwards compatibility is warranted as defined in the package.
• CI jon can be parameterized with a stackVersion. There is a daily job testing with the last 7.x and 8.x snapshots, to know if some package breaks with new versions.

This has some problems:

• Upper bounds of the kibana.version constraints are not checked at any moment.
• Intermediary versions are not checked at any moment.
• Daily jobs attempt to run tests for all packages for the given version, even if the package doesn't support this version.

Some things to do:

• Ensure that at some moment at least the oldest and the newest supported version of a package is checked.
  • Test integrations with latest stack version on PRs #6072
• Fix CI jobs so they don't try to test a package with a version it doesn't support, when the job is launched for an specific stackVersion.
  • Daily job "7.16" should ignore packages with ^8.0.0 compatibility only #2144
• Or, consider having a new daily job that tests packages with their supported matrix.

[botelastic]

Hi! We just realized that we haven't looked into this issue in a while. We're sorry! We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!

[botelastic]

Hi! We just realized that we haven't looked into this issue in a while. We're sorry! We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!

[mrodm]

👍