Add iOS privacy manifests

[JohnSmith0922]

By Apple's Privacy manifest guidelines, some action will be required such as adding an empty privacy manifests file even if you are not collecting anything.

Apple's document: https://developer.apple.com/documentation/bundleresources/privacy_manifest_files See https://github.com/flutter/flutter/issues/131940 for more context.

The following is an example of an empty privacy manifests file if this library is not collecting anything. device_info_plus/ios/PrivacyInfo.xcprivacy

[yukihiro-numata]

@g123k Hey there, I've opened a pull request PR #96. Could you please take a look at it?

[g123k]

Merged in #96