Missing chef-vault cookbook

In a Debian Jessie VM, I'm getting this error when trying to run the cookbook:

==> default: ================================================================================
==> default: Error Resolving Cookbooks for Run List:
==> default: ================================================================================
==> default: 
==> default: 
==> default: Missing Cookbooks:
==> default: ------------------
==> default: No such cookbook: chef-vault
==> default:
==> default:
==> default: Expanded Run List:
==> default: ------------------
==> default: * gitlab-omnibus-builder::default
==> default: 
==> default: 
==> default: Platform:
==> default: ---------
==> default: x86_64-linux
==> default:
==> default:
==> default: [2017-02-18T04:25:28+00:00] ERROR: Running exception handlers
==> default: [2017-02-18T04:25:28+00:00] ERROR: Exception handlers complete
==> default: [2017-02-18T04:25:28+00:00] FATAL: Stacktrace dumped to /root/.chef/local-mode-cache/cache/chef-stacktrace.out
==> default: [2017-02-18T04:25:28+00:00] FATAL: Please provide the contents of the stacktrace.out file if you file a bug report
==> default: [2017-02-18T04:25:28+00:00] ERROR: 412 "Precondition Failed"
==> default: [2017-02-18T04:25:28+00:00] FATAL: Chef::Exceptions::ChildConvergeError: Chef run process exited unsuccessfully (exit code 1)

My setup script is identical to the one given in the readme, so this is after cloning the gitlab-vault repo.