Pin chef-vault version to v3.1.2
chef-vault v4.0.0+ dropped support for Ruby 2.3 (https://github.com/chef/chef-vault/pull/337/). Until we've upgraded all our cookbooks/tests to Ruby 2.6+ and Chef 12+, we should pin the dependency.
Edited by Stan Hu
chef-vault v4.0.0+ dropped support for Ruby 2.3 (https://github.com/chef/chef-vault/pull/337/). Until we've upgraded all our cookbooks/tests to Ruby 2.6+ and Chef 12+, we should pin the dependency.