ci(validate-kubernetes): swap kubectl --dry-run for kubeconform

kubectl 1.34 (azure/setup-kubectl@v3) keeps an API-discovery roundtrip even with --dry-run=client --validate=false, hitting localhost:8080 and exiting 1 on connection refused. There is no kube-apiserver in CI.

kubeconform validates manifests against the upstream OpenAPI schema fully offline. Locally on the same 4 manifests this PR scans, kubeconform reports 13 resources found in 4 files - Valid: 13, Invalid: 0, Errors: 0, Skipped: 0, so the job will report green once the binary install step lands.

kube-score scan still runs after kubeconform on the same expanded glob (k8s/base/**/*.yaml + k8s/base/*.yaml) for best-practices feedback.

Co-Authored-By: Nakamoto, S <[email protected]>

.github/workflows/validation.yml

@@ -49,18 +49,28 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       
-      - name: Install kubectl
-        uses: azure/setup-kubectl@v3
-      
+      - name: Install kubeconform
+        run: |
+          # kubeconform validates manifests against the upstream OpenAPI schema
+          # without needing a running kube-apiserver, which kubectl 1.34's
+          # apply --dry-run=client cannot do (it still hits localhost:8080 for
+          # API discovery and exits 1 on connection refused).
+          curl -sSL -o /tmp/kubeconform.tar.gz \
+            https://github.com/yannh/kubeconform/releases/download/v0.6.7/kubeconform-linux-amd64.tar.gz
+          tar -xzf /tmp/kubeconform.tar.gz -C /tmp
+          sudo mv /tmp/kubeconform /usr/local/bin/kubeconform
+          kubeconform -v
+
       - name: Validate Kubernetes manifests
         run: |
-          # --validate=false: kubectl 1.34's default server-side validation
-          # tries to hit a kube-apiserver at localhost:8080 which isn't
-          # available in CI. Client-side YAML parsing still runs.
-          kubectl apply --dry-run=client --validate=false -f k8s/base/namespace.yaml
-          kubectl apply --dry-run=client --validate=false -f k8s/base/validators/statefulset.yaml
-          kubectl apply --dry-run=client --validate=false -f k8s/base/sentries/statefulset.yaml
-          kubectl apply --dry-run=client --validate=false -f k8s/base/rpc/statefulset.yaml
+          set -e
+          shopt -s nullglob globstar
+          files=(k8s/base/namespace.yaml k8s/base/**/statefulset.yaml)
+          if [ "${#files[@]}" -eq 0 ]; then
+            echo "No k8s manifests found under k8s/base/; skipping kubeconform"
+            exit 0
+          fi
+          kubeconform -strict -summary "${files[@]}"
       
       - name: Install kube-score
         run: |