Use new submit for review API

[dalemyers]

The old version of this API has been deprecated and will no longer work from June 9th: https://developer.apple.com/documentation/appstoreconnectapi/post-v1-appstoreversionsubmissions

This moves to the new API.

Note: I haven't been able to test this yet. @JasperGuo / @Cokile if you have a test app you can test this with, it would be appreciated!

[Copilot]

Pull Request Overview

This PR updates the API submission method to use the new review endpoint, reflecting the deprecation of the old API.

• Changed API endpoint from "appStoreVersionSubmissions" to "reviewSubmissions" and adjusted the related data structure
• Added a new required parameter "platform" in the submit_for_review method and updated the corresponding README example

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
asconnect/version_client.py	Updated API endpoint, payload structure, and method signature for new platform support
README.md	Updated usage example to include the new platform parameter

Comments suppressed due to low confidence (2)

asconnect/version_client.py:443

• The new 'platform' parameter is introduced without corresponding tests. Please add tests to verify its behavior, including handling of valid platform values and error scenarios.

+        platform: Platform,

README.md:69

• The usage example assumes access to the Platform enum. Please ensure that the example includes an import statement or clear instructions on how to reference the Platform enum.

client.version.submit_for_review(version_id=version.identifier, platform=Platform.IOS)

[Cokile]

FYI: we tried to migrate to use the new API before, and fixed some bugs: #46, #47, but the API seems not work as expected, so we reverted it back: #50

[dalemyers]

FYI: we tried to migrate to use the new API before, and fixed some bugs: #46, #47, but the API seems not work as expected, so we reverted it back: #50

That's somewhat annoying. It's been a year though, so maybe things have improved? The API we were using is going away, so I don't think we have much choice but to go with this approach and try and deal with issues if/when they come up?