golangci-lint: synchronize configs and add verification for that

https://github.com/kubernetes/kubernetes/pull/109728 added a
golangci-strict.yaml where gingkolinter and stylecheck (some recent additions
to golangci.yaml) were missing.

To prevent such mistakes in the future, lines that are intentionally different
get annotated with a comment about golangci-strict.yaml or golangci.yaml.
Then a suitable diff command in the new verify-golangci-lint-config.sh checks
that only such lines, comments and blank lines are different.

hack/verify-golangci-lint-config.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+
+# Copyright 2023 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script checks that golangci-strict.yaml and golangci.yaml remain in
+# sync. Lines that are intentionally different must have a comment which
+# mentions golangci.yaml or golangci-lint.yaml.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+KUBE_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
+
+if differences=$(diff --context --ignore-blank-lines \
+                      --ignore-matching-lines='^ *#' \
+                      --ignore-matching-lines='#.*golangci\(-strict\)*.yaml' \
+                      "${KUBE_ROOT}/hack/golangci.yaml" "${KUBE_ROOT}/hack/golangci-strict.yaml" ); then
+    echo "hack/golangci.yaml and hack/golangci-strict.yaml are synchronized."
+else
+    cat >&2 <<EOF
+Unexpected differences between hack/golangci.yaml and hack/golangci-strict.yaml:
+
+${differences}
+
+If these differences are intentional, then add comments at the end of each
+different line in both files that mention golangci-strict.yaml or
+golangci.yaml.
+EOF
+    exit 1
+fi