Adding that Vault server can be Open Source or Enterprise versions

doc/ci/examples/authenticating-with-hashicorp-vault/index.md

@@ -22,7 +22,8 @@ This tutorial assumes you are familiar with GitLab CI/CD and Vault.
 To follow along, you will need:
 
 - An account on GitLab.
-- A running Vault server and the access required to configure authentication and create roles and policies.
+- A running Vault server and access to it is required to configure authentication and create roles
+  and policies. For HashiCorp Vaults, this can be the Open Source or Enterprise version.
 
 NOTE: **Note:**
 You will need to replace the `vault.example.com` URL below with the URL of your Vault server and `gitlab.example.com` with the URL of your GitLab instance.