ci: use golangci-lint v2

[PascalBourdier]

update golangci-lint to v2 and use autofix

Description of the change:
update golangci-lint to v2

Motivation for the change:
allow golangci-lint v2 features usage

Checklist

If the pull request includes user-facing changes, extra documentation is required:

• Add a new changelog fragment in changelog/fragments (see changelog/fragments/00-template.yaml)
• Add or update relevant sections of the docs website in website/content/en/docs

[PascalBourdier]

sanity / docs check failed with:

External link https://kuttl.dev/docs/testing/reference.html#testsuite failed: response code 0 means something's wrong.

but no DNS entry seems present for kuttl.dev