Add "format" field for uint32 and uint64

[paulyoung]

We noticed that for int32 and int64 fields we were able to check the format field and decode an int64 value to a BigInt in PureScript (ultimately JavaScript) but for uint32 and uint64 that field wasn't present.

This pull request adds that field along with a test to verify that it works as expected.

[fisx]

Nice, thanks!

I'm wondering about the shorter words though. Do they behave differently in purescript / js? Should we?

[paulyoung]

To my knowledge, the Swagger 2 spec only provides int32 and int64 for format. I’m not sure if the former should be used for smaller sizes.

On the plus side it might allow us to use PureScript’s Int type instead of Number. On the down side, some consumers might be concerned about using a larger sized integer than is necessary.

[paulyoung]

I'm beginning to think we should perhaps have just looked at the minimum and maximum fields all along...

[paulyoung]

Apparently the format is necessary because the wire type may not actually be a number.

[paulyoung]

More specifically, the min and max is not enough information to determine if it’s an integer that’s a numeric type, or an integer that’s actually a string.

[paulyoung]

Using int32 for uint32 (for example) does mean we'd need to check the minimum field in order to determine whether to use a PureScript Int or Number (respectively) since Int doesn't cover the full range of unsigned integers.

[fisx]

I can't see any downsides in what you're providing, nor any obvious improvements, so, merge! But feel free to open another PR if you can think of anything else.

Thanks again!