Attach dependencies to the DependencyFile in go_modules's FileParser

[phillmv]

What are you trying to accomplish?

Per https://github.com/github/dependency-graph/issues/7121,

[for those of you who do not work at GitHub, the above link describes an effort we're undergoing to refactor technical debt and start using dependabot-core to parse dependencies for our dependency graph service.]

This PR attaches Go dependencies to the associated DependencyFile in Dependabot::GoModules::FileParser.

Back in #12768 we introduced DependencyFile#dependencies and in this PR we extend its usage to the go_modules ecosystem, in support of the DependencySubmission functionality introduced in #12734

Anything you want to highlight for special attention from reviewers?

I feel its pretty straightforward!

How will you know you've accomplished your goal?

Tests pass, testing in production.

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.

[brrygrdn]

👍🏻 LGTM

EDIT: Ah damn, it looks like CI is unhappy - my PR build off this didn't fail in the same way so it might be a flake?