[iOS] Missing `ios/RnDiffApp.xcworkspace/contents.xcworkspacedata` file

Bug

Some versions of the upgrade helper are missing the contents.xcworkspacedata.

This is happening because the Ruby environment is not set properly and the script fails to:

1. install the dependencies.
2. create the expected files.

Example failure

The script ignore the failure and proceeds with the job, publishing the diff anyway.

React Native versions

• 0.63.5 - observe that the RnDiffApp.xcworkspace/contents.xcworkspacedata file is missing
• 0.64.4 - observe that the RnDiffApp.xcworkspace/contents.xcworkspacedata file is missing
• 0.65.3 - observe that the RnDiffApp.xcworkspace/contents.xcworkspacedata file is missing
• 0.66.5 - observe that the RnDiffApp.xcworkspace/contents.xcworkspacedata file is missing
• 0.68.5 - observe the failure in CI
• 0.69.7 - observe the failure in CI
• 0.70.4 - observe the failure in CI
• 0.70.5 - observe the failure in CI
• 0.71.0-rc.0 - observe the failure in CI

Steps to reproduce

Run the script and see the Cocoapods failure.

Suggested fix

The suggested fix would be to update the new-release.sh script so that:

1. It installs rbenv (or a similar Ruby Management system
2. curl the right Ruby version for ReactNative when releasing a new version. It should use the version tags to learn where to look. Example for v0.70.X
3. Install the right ruby version
4. Set the ruby version as global version
5. Proceed with the standard execution.

As an additional safety net, the script should fail if the dependencies are not installed correctly, with a proper error message.

[pvinis]

I think I will close this issue, and lets open it up again if any of the above is not clear or not working. I feel confident for everything, though.

[pvinis]

I regenerated the problematic 0.67.5 too, so now the new diffs will not have any vendor stuff in the diffs.