fix: refactor for newspack-scripts dependency updates

[dkoo]

All Submissions:

• [x] Have you followed the Newspack Contributing guideline?
• [x] Does your code follow the WordPress' coding standards and VIP Go coding standards?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Refactoring required for changes in https://github.com/Automattic/newspack-scripts/pull/209. Note that this PR will not pass CI tests and should NOT be merged until https://github.com/Automattic/newspack-scripts/pull/209 is released as an NPM package, so this repo can install it as a dependency.

How to test the changes in this Pull Request:

Follow instructions in https://github.com/Automattic/newspack-scripts/pull/209.

Other information:

• [x] Have you added an explanation of what your changes do and why you'd like us to include them?
• [ ] Have you written new tests for your changes, as applicable?
• [x] Have you successfully ran tests with your changes locally?

[matticbot]

:tada: This PR is included in version 0.7.2-alpha.1 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket:

[matticbot]

:tada: This PR is included in version 0.7.2 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: