Fixes default PUPPET_DESTRUCTIVE value

When using this repository and running `bundle exec librarian-puppet install`, librarian-puppet changes the value of the `LIBRARIAN_PUPPET_DESTRUCTIVE` key from `true` to `false`. This commit changes the default value.
Merge pull request #7 from gds-operations/fix-libpuppet-config

Fixes default PUPPET_DESTRUCTIVE value
Updates `librarian-puppet`

The librarian-puppet gem has been renamed from `librarian-puppet-maestrodev`
to `librarian-puppet`. This commit makes that change. It does not lock the
version in the Gemfile, as the Gemfile.lock does this instead.
Merge pull request #8 from gds-operations/update-libpuppet-version

Updates 'librarian-puppet'
Change path and exec method in Puppet

This commit is prior art from alphagov/govuk_mirror-puppet#31ec3c
(https://github.com/alphagov/govuk_mirror-puppet/commit/31ec3c6e038326e9f152c01e3ea0dee4de2aae63).
From its commit message:

Replace Vagrant's builtin provisioner for Puppet with our own shared folder and
shell script. This will allow us to use a consistent filesystem path in Vagrant
and production which is useful for Hiera, in particular, because unlike
extlookup the `datadir` path can't be computed relative to another Puppet
variable.
Merge pull request #9 from gds-operations/change-path-exec-puppet

Change path and exec method in Puppet
Merge remote-tracking branch 'skeleton/master' into change-path-exec-puppet

This pull request:

- replaces Vagrant's built-in provisioner with a custom-written shared folder
  and shell script provisioner. This allows us to use a consistent filesystem
  path in Vagrant and production which is useful for Hiera in particular because
  unlike extlookup, the datadir path can't be computed relative to another
  Puppet variable.

- updates the version of `librarian-puppet` in use

- fixes the default `PUPPET_DESTRUCTIVE` value, per
  https://github.com/gds-operations/puppet-skeleton/commit/fdee1788babe4b6e3c947cf289c9877c2b86f6db
Merge pull request #17 from alphagov/change-path-exec-puppet

Change path exec puppet