Add note about plugin_directory (#7584)
Add note about plugin_directory (#7584)

- Note that plugin_directory cannot be a symbolic link
rnaveiras/vault,rnaveiras/vault,rnaveiras/vault,kingland/vault,hashicorp/vault,hashicorp/vault,joelthompson/vault,hashicorp/vault,quixoten/vault,hashicorp/vault,hartsock/vault,hartsock/vault,hashicorp/vault,joelthompson/vault,hartsock/vault,kingland/vault,kingland/vault,quixoten/vault,joelthompson/vault,rnaveiras/vault,hartsock/vault,rnaveiras/vault,hartsock/vault,hashicorp/vault,kingland/vault,quixoten/vault,quixoten/vault,kingland/vault,joelthompson/vault