auto-upgrade: variable orchestrator_version to null

[zioproto]

Describe your changes

This is an addition to PR #281

In AKS is possible to upgrade the control plane and the kubernetes nodes independently. The Terraform resource azurerm_kubernetes_cluster exposes this with 2 variables kubernetes_version and orchestrator_version.

In PR #281 the lifecycle validation check takes into account only kubernetes_version.

Issue number

Related to #280

[the-technat]

Thanks for coming up with this! I totally forgot about the orchestrator_version, but now that you told me about the actually behavior of the nodes, it makes sense to omit this when automatic upgrades are turned on.

[lonegunmanb]

Thanks @zioproto for opening this pr and thanks @the-technat for participating our discussion. Almost LGTM but I'd like to simplify the logic expression. And since this expression is very complex, would you please add some unit test cases to cover the cases related to var.orchestrator_version? I would recommend adding the new unit tests first to prove your expression works, then try my suggestion with protection from these tests. With the protection from your test cases, we could change or refactor this expression in the future. Thanks @zioproto !

[zioproto]

@lonegunmanb please take a look again

[lonegunmanb]

Hello @zioproto , I'm sorry we've met an issue on our pipeline so we have to upgrade the Github action yaml files in this repo, would you please merge your branch with the latest master branch so we can run the e2e test? Apology for the inconvenience, we're still refactoring the pipeline.

[zioproto]

@lonegunmanb I rebased my commit on top of the current master branch. Thanks

[lonegunmanb]

Thanks @zioproto , LGTM! 🚀