Testing Matrix

The operator should be tested on a variety of Kubernetes version, from the lowest we support to the latest available.

We should nightly as well as on pull-requests (running them in parallel). Today, we only have one check which is pull-tekton-operator-integration-tests. Instead we should have several of them, one per k8s version we "support". We do not necessarily need to run the full test-suites on all version (if they are taking ages), but a selected number that should cover the basis (and most components if not all).

• We can go the chains route and start by using GitHub workflows (and kind)
• We can then (or initially) go the tekton+matrix routes and hook the dogfooding tekton cluster to this repository.

I would suggest we should go ahead with the GitHub workflow to work on the "tooling" to do this. Porting it to tekton then should be relatively straightforward.

cc @tektoncd/operator-maintainers

Note: e.g. tektoncd/chains is doing that on pull-request (like here)

Start with the existing pull-tekton-operator-integration-tests check and compare the GitHub workflow approach used by tektoncd/chains. Identify the lowest and latest supported Kubernetes versions and how kind can run the selected integration tests in parallel on pull requests and nightly. Done means separate version checks cover the support range without requiring the full suite for every version.