[build]: add tests for dockerfile arg parsing

[saehejkang]

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Motivation and Context

Relates to #1295

Test cases added for validation based on changes from apple/container-builder-shim#70.

Testing

• Tested locally
• Added/updated tests
• Added/updated docs

[jglogan]

@JaewonHur added you as reviewer after you sign off and merge apple/container-builder-shim#70, and tag the updated builder.

@saehejkang Once there's a new container-builder-shim tag, could you update this PR to reference the latest builder release in Package.swift?

[saehejkang]

Note: CI is expected to fail until apple/container-builder-shim#70 is merged and the new release of the shim is referenced

[saehejkang]

Once there's a new container-builder-shim tag, could you update this PR to reference the latest builder release in Package.swift?

yes, I will make those changes here

[JaewonHur]

Hi @saehejkang !
I updated tag 0.11.0 in container-buider-shim. Could you update this PR to point that tag and test again?

[jglogan]

@saehejkang If you can get the version update in such that the build works in the next couple hours, we can include this in 0.11.0.

[jglogan]

@saehejkang If you can get the version update in such that the build works in the next couple hours, we can include this in 0.11.0.

I did a 0.11.0 update and patched your test changes in, worked fine!

Merged the update and then merged that into the PR, testing now. 🤞

[jglogan]

@saehejkang Thank you for adding these tests! Merged.

[saehejkang]

If you can get the version update in such that the build works in the next couple hours, we can include this in 0.11.0.

@jglogan Apologies for not being able to make these changes when you asked.