Fixes default PUPPET_DESTRUCTIVE value
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.

gds-operations/puppet-skeleton,alphagov/govuk_offsitebackups-puppet,russmckendrick/puppet-skeleton,op-ct/puppet-skeleton,alphagov/govuk_offsitebackups-puppet