Add targets to package.toml to support multi-arch

[jericop]

Summary

This change:

• Adds targets to package.toml to support multi-arch
• Switches from cnb URIs to registry URIs in package.toml

Use Cases

multi-arch 🥳 🎉

Checklist

• I have viewed, signed, and submitted the Contributor License Agreement.
• I have linked issue(s) that this PR should close using keywords or the Github UI (See docs)
• I have added an integration test, if necessary.
• I have reviewed the styleguide for guidance on my code quality.
• I'm happy with the commit history on this PR (I have rebased/squashed as needed).