Deprecation of UIWebView

### New Issue Checklist

- [x] I have tried with the latest version of OHHTTPStubs
- [x] I have read the [README](https://github.com/AliSoftware/OHHTTPStubs/blob/master/README.md)
- [x] I have read the [Using the right Swift Version of `OHHTTPStubs` for your project](https://github.com/AliSoftware/OHHTTPStubs#using-the-right-swift-version-of-ohhttpstubs-for-your-project) section
- [x] I have searched in the [existing issues](https://github.com/AliSoftware/OHHTTPStubs/issues?utf8=✓&q=is%3Aissue)
- [x] I have read [the OHHTTPStubs wiki](https://github.com/AliSoftware/OHHTTPStubs/wiki) to see if there wasn't a detailed page talking about my issue

### Environment

- version of OHHTTPStubs: [7.0.0]
- integration method you are using:
* [ ] Cocoapods
* [x] Carthage
* [ ] submodule
* [ ] other
- version of the tool you use: [0.35.0]

### Issue Description

Apple will begin to reject apps the utilize UIWebView as of December 2020. It seems like AFNetworking is the cause for OHHTTPStubs being flagged in my audit. AFNetworking seems to have resolved this issue in version 4.0.