fix: validate workflow

.github/workflows/validate-k8s.yml

@@ -37,7 +37,15 @@ jobs:
           version: 'v3.9.0'
 
       - name: Install Helm Diff plugin
-        run: helm plugin install https://github.com/databus23/helm-diff || true
+        env:
+          HELM_PLUGINS: /home/runner/.local/share/helm/plugins
+        run: |
+          mkdir -p "$HELM_PLUGINS"
+          if ! helm plugin list | grep -q '^diff'; then
+            helm plugin install https://github.com/databus23/helm-diff
+          fi
+          helm plugin list
+          helm diff version
 
       - name: Determine DNS_HOST based on environment
         id: set_dns
@@ -105,4 +113,5 @@ jobs:
       - name: Run Helmfile Diff
         env:
           ENV: ${{ needs.extract_environment.outputs.environment }}
+          HELM_PLUGINS: /home/runner/.local/share/helm/plugins
         run: helmfile -f deploy/helmfiles/${ENV}.yaml diff