Added a variant of the test that uses HashiCorp Vault to manage te

Certificate Authorities.

vault_gcp_update.sh

@@ -0,0 +1,20 @@
+source ./env.sh
+
+# Generate the trust store from the Vault CA certificates
+node make_trust_store.mjs
+
+# Replace the trust store of the existing X.509 provider
+gcloud iam workload-identity-pools providers update-x509 "${PROVIDER_ID}" \
+  --project="${PROJECT_ID}" \
+  --location=global \
+  --workload-identity-pool="${POOL_ID}" \
+  --trust-store-config-path=trust_store.yaml
+
+# Show the provider configuration
+gcloud iam workload-identity-pools providers describe "${PROVIDER_ID}" \
+  --project="${PROJECT_ID}" \
+  --location=global \
+  --workload-identity-pool="${POOL_ID}"
+
+# Test the federation with the client certificate issued by Vault
+gcloud storage ls "gs://${BUCKET}" --configuration=wif-test