Update checksums for 0.7.1

Thanks for updating things to the 0.7.0 version. Here are the changes for 0.7.1.

I also did some work to [relax the version constraint on the ark dependency](https://github.com/tdg5/chef-packer/compare/update_ark). If that's of any use to you, let me know and I can make another PR or you can just steal the diff.