chore: chmod +x the binaries before wrapping in tarball

[jchillerup]

I had some issues installing this tool with mise because the binaries were not chmod +x prior to packaging.

This PR implements exactly that and nothing more :)

When this is integrated it should be able to add ipatool to your mise environment like so:

$ mise use ubi:majd/ipatool

[Copilot]

Pull Request Overview

This PR fixes executable permissions for binary files before creating release tarballs to resolve installation issues with mise package manager. The change ensures binaries are properly executable when extracted from the distributed archives.

• Added chmod +x commands before tarball creation in GitHub Actions workflow
• Applied the fix to both Linux and macOS binary packaging steps

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