Support scanning Flutter iOS packages

[timo-HERE]

What is the feature you want to request?

When scanning Flutter projects, there are all these warnings:

Cannot get iOS dependencies for package '$packageName'. Support for CocoaPods is not yet implemented. 

Describe the solution you would like

Implement the missing functionality of Pub.analyzeIosPackages() similar to Pub.scanAndroidPackages()

Alternatives you have considered

I have tried to scan the project with CocoaPods, but it does not support local Podfiles (#5175) so the results are incorrect.

Using VCS URL and revisions is nearly impossible as Podspec versions are ambiguous: tekartik/sqflite@775f070 shows how version Pod::sqflite:0.0.3 matches Pub::sqflite versions v2.3.3+1 , v2.3.3, v2.3.2, v2.3.2-2, v2.3.2-1, v2.3.1, and v2.3.0

Additional context

ort/plugins/package-managers/pub/src/main/kotlin/Pub.kt

Line 473 in a45bd86

// TODO: Implement similar to `scanAndroidPackages` once CocoaPods is implemented.

#8343

[sschuberth]

I have tried to scan the project with CocoaPods, but it does not support local Podfiles (#5175) so the results are incorrect.

So would it even help to have Cocoapods support in Pub if Cocopods does not support local podspecs yet?

[timo-HERE]

I have tried to scan the project with CocoaPods, but it does not support local Podfiles (#5175) so the results are incorrect.

So would it even help to have Cocoapods support in Pub if Cocopods does not support local podspecs yet?

I have no idea how these two missing features are linked. 🤷

[sschuberth]

I have no idea how these two missing features are linked. 🤷

Well, you yourself wrote

I have tried to scan the project with CocoaPods, but it does not support local Podfiles (#5175) so the results are incorrect.