added error type StripeIdempotencyError

[yotamshacham]

No description provided.

[ob-stripe]

Hi @yotamshacham, thanks for the contribution!

This looks alright to me, but I know that @brandur-stripe was working on a similar feature for the Ruby library a few months back (cf. stripe/stripe-ruby#503), so I'll defer to him. He's away right now but will be back next week. Thanks for your patience!

r? @brandur-stripe

[brandur-stripe]

Thanks @yotamshacham!

This looks alright to me, but I know that @brandur-stripe was working on a similar feature for the Ruby library a few months back (cf. stripe/stripe-ruby#503), so I'll defer to him. He's away right now but will be back next week. Thanks for your patience!

I think I forgot to mention it, but I ended up merging a formalized idempotency_error type in the backend implementation so stripe/stripe-ruby#503 is unblocked.

This one is also good to come in!

[brandur-stripe]

Released as 5.4.0.