chore: fix test command in readme

Author: tobikris

README.md

@@ -18,4 +18,4 @@ Unit tests can be run normally by cargo: `cargo test`.
 End-to-end tests require a Kubernetes cluster and will install, upgrade and uninstall (except on failure) several deployments of a Vault cluster in the current `kubecontext` (namespace is set by environment variable `VAULT_MGMT_E2E_NAMESPACE`, defaulting to `vault-mgmt-e2e`). You can create the Namespace and NetworkPolicy from `e2e-preparation.yaml`.
 The Pods are using `emptyDir` as storage and should not consume a PV.
 The storage is not part of the tests, only the clustering and active/standby transitions.
-You can run those tests by calling `cargo test --ignored` with a working `kubeconfig` and existing namespace.
+You can run those tests by calling `cargo test -- --ignored` with a working `kubeconfig` and existing namespace.