Add support for decimal pricing and transform_usage

[magni-]

I haven't written Go in years (and never wrote much to begin with), but hopefully this looks good.

I only updated Stripe to the version that added support for decimal pricing, should I instead bump it up to the latest?

edit: ~indenting looks all over the place in the diff despite being fine in my editor, will fix~ fixed

make test doesn't pass yet, will update when it does.

[magni-]

Tests pass locally:

# clean Stripe test account, no `terraform.tfstate` file to start

$ make test
...
Apply complete! Resources: 10 added, 0 changed, 0 destroyed.
...
$ make test
...
Apply complete! Resources: 0 added, 0 changed, 0 destroyed.
...

Things look good in Stripe as well:

[magni-]

Salut @franckverrot!

It's late here, I didn't realize you had commented 🤦‍♂ This should be ready for review now.

[magni-]

We're now using this branch in production at RainforestQA, working great 👍

[franckverrot]

Awesome, thanks, do you mind giving the official release a try? https://github.com/franckverrot/terraform-provider-stripe/releases/tag/1.4.0

Thanks!

[franckverrot]

oh, merged offline also, I had to update one of your commit to vendor the dependencies and squashed the 3 other ones.