2.0.0 Support Savings plan

Support Savings plan.

If you're reading the Parser's output CSV file yourself instead of using the Coster, this could potentially be a breaking change as I've added additional columns at the end.

1.0.0 Fix software without hybrid benefit

The parser would fail if hybrid benefit wasn't available, which is most of the software. I added an end-to-end test for ubuntu-advantage-essential to cover this scenario.