class Chef::Knife::Bootstrap::ChefVaultHandler

}
"vault2": [ "item1", "item2", "item2" ]
"vault1": "item",
{

or an Array of Strings:
Iterate through all the vault items to update. Items may be either a String

def update_bootstrap_vault_json!
  vault_json.each do |vault, items|
    [ items ].flatten.each do |item|
      update_vault(vault, item)
    end
  end
end