AO CI: Updating the CI system to install and run minikube

[galmasi]

Just a small step in the direction of fully integrated test the attestation operator.

[galmasi]

I have removed the "do not merge" label. However, the GH action will not run correctly on PRs from forked repositories until after this current PR is merged. Please merge this, and I will open another PR right away just to test whether we can get a pass from GHA this time.

For those interested in the minutiae -- the difference is between marking an action "pull_request" vs "pull_request_target"; for the former, the commit triggering the workflow is the last commit on the branch that is subject of the pull request; for the latter, the branch triggering the workflow is the base branch from which the workflow is derived. The latter is marginally safer, and therefore GH allows the secrets associated with the repo owner organization onto it.