Revert to puppet-go 1.1.0

This upgrade to 2.0.1 was overlooked when I merged #519, and breaks
things for people who use zsh (see boxen/puppet-go#8).
Merge pull request #523 from boxen/revert-to-puppet-go-1-1-0

Revert to puppet-go 1.1.0
Amend placeholder file extension

Fixes #534