The puppet version used by bundle is set as:
Debian Jessie came with 3.7.2 so we probably to stick to that, though that probably does not matter much ( upstream changelog is https://docs.puppet.com/puppet/3.7/release_notes.html#puppet-375 ).
The subject of this task is: what is the actual version of puppet running in the box? Maybe it is using 3.8.x which we had at some point or maybe it is even already on puppet 4?
The reason is to be able to run rspec puppet tests with the same version as on the box.