implement/fix reverse iteration when iterating with ending_before

[kaznovac]

fixes #1090

implementation, similarly to stripe/stripe-dotnet#1848, reverses the order of the response list to prevent unexpected iteration
(example without reversing described in https://github.com/stripe/stripe-dotnet/pull/1854/files#r350498976)

[mnooblet]

nice, can we get this merged please?

[remi-stripe]

We'll get to it in early January after the holidays!

[mnooblet]

We'll get to it in early January after the holidays!

great, happy new year ;)

[richardm-stripe]

Hi @kaznovac, very grateful for this PR! Thank you especially for the tests. I just have one request to avoid .reverse().

[richardm-stripe]

Wrote a couple of extra tests while reviewing this to make sure I understood this change. You can merge them into your branch if you'd like, otherwise I will merge it afterwards:

kaznovac/stripe-node@reverse-iteration...richardm-stripe:richardm-reverse-iteration

Lots of whitespace noise because I added a describe unfortunately, but the new tests are

kaznovac/stripe-node@reverse-iteration...richardm-stripe:richardm-reverse-iteration#diff-4e53030d8c08ab9ded8e272ce6840dec73ec6d10d746382502f274378da2a474R529-R542

and

kaznovac/stripe-node@reverse-iteration...richardm-stripe:richardm-reverse-iteration#diff-4e53030d8c08ab9ded8e272ce6840dec73ec6d10d746382502f274378da2a474R580-R697

[richardm-stripe]

Thank you so much for the contribution @kaznovac, we'll get this released shortly.

[mnooblet]

@kaznovac @richardm-stripe thank you guys 🍺