Support both old & new structs for moderation.go

[galpt]

This should fix the error:
json: cannot unmarshal number into Go struct field ResultCategories.results.categories.hate of type bool

Looking at this comment, it seems that OpenAI still haven't applied the new changes, and the previous pull request will cause the above json error.

I decided to include both the current moderation struct & the new struct that will likely be used in the near future.

[galpt]

Since it's starting tomorrow (Friday, August 5th 2022), I guess I would test it again tomorrow to see if anything breaks, and this pull request can wait until August 6th.
Might as well remove the old structs to make the code clean.

[galpt]

I'm closing this as the previous pull request should work just fine with the new Moderations endpoint changes.
An email about this:

Hi there,

Thanks for being a user of OpenAI’s Moderations endpoint. I’m following up to inform you that the following breaking change in our API is now live. The type of moderation endpoint response fields flagged and each field in categories have changed from Integer to Boolean. Return values that were 1 are now true and return values of 0 are now false. Below is an example output of the updated endpoint.

If your application relies on these fields being integers, please update your code to rely on booleans. Otherwise no action is required on your end.

Please reach out to support@openai.com if you have any concerns with this change. Thanks!

{
  "id": "modr-XXXXX",
  "model": "text-moderation-001",
  "results": [
    {
      "categories": {
        "hate": false,
        "hate/threatening": false,
        "self-harm": false,
        "sexual": false,
        "sexual/minors": false,
        "violence": false,
        "violence/graphic": false
      },
      "category_scores": {
        "hate": 0.18805529177188873,
        "hate/threatening": 0.0001250059431185946,
        "self-harm": 0.0003706029092427343,
        "sexual": 0.0008735615410842001,
        "sexual/minors": 0.0007470346172340214,
        "violence": 0.0041268812492489815,
        "violence/graphic": 0.00023186142789199948
      },
      "flagged": false
    }
  ]

Best,
Angela