Rename kustomization arg from validate to validation

Fix `tk create kustomization` command args inconsistency with the Kustomize API

.github/workflows/e2e.yaml

@@ -65,7 +65,7 @@ jobs:
             --path="./deploy/overlays/dev" \
             --prune=true \
             --interval=5m \
-            --validate=client \
+            --validation=client \
             --health-check="Deployment/frontend.dev" \
             --health-check="Deployment/backend.dev" \
             --health-check-timeout=3m