feat: Swift Package Manager support

[rekire]

Description

The template generator should use the Swift Package Manager, the documentation mentions also the required parts to keep the "legacy" CocoaPods support.

Requirements

• All CI/CD checks are passing.
• There is no drop in the test coverage percentage.

Additional Context

No response

[tomarra]

Hi @rekire 👋 Thanks for opening this issue.

We are aware of the move to Swift Package Manager and are excited for it to land. Given that right now it's only available in the main Flutter branch and not in a stable release we won't prioritize the work given that it's not a breaking change. When the SPM implementation lands the Cocoapods implementation will still be supported for sometime. When that happens we can re-evaluate this work and ensure that we can migrate safely and not effect the templates.

[rekire]

That feature is now live in 3.27

[tomarra]

Notes from Grooming Session with team

• While support for this is released with 3.27 there is still an overarching message on the documentation saying "Swift Package Manager support is off by default. Flutter continues to support CocoaPods." Given this we shouldn't jump straight into this as the community packages still need to be updated as well.
• We should take the time to look at this for very_good_flutter_plugin as this seems like the main one that would be effected. But again need to be cautious as to when we turn this support on.

[rekire]

The changes are not so big, to be honest. It is primarily a change of the folder structure, especially when you have no code yet. The CocoaPods usage of the same does not break. You just need to update the path.