Update docs to use_framework! (#3324)
Update docs to use_framework! (#3324)

Summary:
Cannot run app if we use use_framework in cocoapods, because Flipper-Fmt need to add $static_frameworks

## Changelog

Pull Request resolved: https://github.com/facebook/flipper/pull/3324

Test Plan:
Imported from GitHub, without a `Test Plan:` line.

**Static Docs Preview: flipper**
|[Full Site](https://our.intern.facebook.com/intern/staticdocs/eph/D33686186/V3/flipper/)|

|**Modified Pages**|
|[docs/getting-started/ios-native](https://our.intern.facebook.com/intern/staticdocs/eph/D33686186/V3/flipper/docs/getting-started/ios-native/)|

Reviewed By: passy

Differential Revision: D33686186

Pulled By: lblasa

fbshipit-source-id: d628a79c768cd2f56454b194773f4f592bdbe7c6

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper