New release from develop > 2.0.0

It seems like an octane upgrade was merged to develop last Feb with plans to cut a new release.

I believe the new release as it currently exists would close #6 #27 #30

I will need to use this addon in the next few weeks/months so I may be able to spend time on this myself when I come to it on my current project, for example I think I could cover

1. Updating the load method to use the official stripe loader as outlined in #25
2. Adding a withRetry method to enable retrying a failed stripe load as outlined in #22
3. Moving test support to `addon-test-support` dir as outlined in #21
4. Adding the `update` method to the stripe mock to close #8
5. Adding the new "Payment" element as a glimmer component https://stripe.com/docs/payments/payment-element

I can't start on this right away, but I do plan to come back and visit this when I get to the payments part of my current project.