The voting in https://github.com/kubernetes/kubernetes/issues/117288 led to
one check that got rejected ("ifElseChain: rewrite if-else to switch
statement") and several that are "nice to know".
golangci-lint's support for issue "severity" is too limited to identify "nice
to know" issues in the output (filtering is only by linter without considering
the issue text; not part of text output). Therefore a third configuration gets
added which emits all issues (must fix and nits). The intention is to use
the "strict" configuration in pull-kubernetes-verify and the "hints"
configuration in a new non-blocking pull-kubernetes-linter-hints.
That way, "must fix" issues will block merging while issues that may be useful
will show up in a failed optional job. However, that job then also contains
"must fix" issues, partly because filtering out those would make the
configuration a lot larger and is likely to be unreliably (all "must fix"
issues would need to be identified and listed), partly because it may be useful
to have all issues in one place.
The previous approach of manually keeping two configs in sync with special
comments didn't scale to three configs. Now a single golangci.yaml.in with
text/template constructs contains the source for all three configs. A new
simple CLI frontend for text/template (cmd/gotemplate) is used by
hack/update-golangci-lint-config.sh to generate the three flavors.
