Implement tests for plugin utils (dependencies scanner)

[mateusz1913]

Discussed in #25

^{Originally posted by mateusz1913 March 14, 2025}
Would be great to have some unit tests for different examples:

• single repo project
• monorepo project
• monorepo project with workspace: dependencies
• packages with @ and / characters in their names

When tests are implemented, those could be run as a pre-push git hook and on CI for pull requests (this can be done as a separate issue)