[WIP] Do not require upgrade_cluster_setup=true for unsafe upgrades

[Miouge1]

What type of PR is this?
/kind bug
/kind cleanup

What this PR does / why we need it:
cluster.yml used to be able to upgrade a cluster without drains, which is useful in some cases. Adding the upgrade_cluster_setup=true was introduced in #5339

Which issue(s) this PR fixes:

Related to #5609

Special notes for your reviewer:
Also exclude .git dir from yamlint otherwise it gets confused with branches ending in .yml
Does this PR introduce a user-facing change?:

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Miouge1

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [Miouge1]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[fejta-bot]

Unknown CLA label state. Rechecking for CLA labels.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/check-cla

[k8s-ci-robot]

@Miouge1: The following test failed, say /retest to rerun all failed tests:

Test name	Commit	Details	Rerun command
pull-kubespray-yamllint	5f1a8f0	link	/test pull-kubespray-yamllint

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[fejta-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/lifecycle stale