fix(nodejs): change the type of the devDependencies field

[nikpivkin]

Description

Scanning a v6 lock file with dev dependencies outputs the following error:

Analysis error: unable to parse pnpm-lock.yaml: failed to parse pnpm-lock.yaml: failed to parse pnpm-lock.yaml: decode error: yaml: unmarshal errors:
  line 8: cannot unmarshal !!map into string
…
  line 171: cannot unmarshal !!map into string

I changed the type of the devDependencies field, because in v6 lock file it is a structure and not a string.

Related issues

• Close PNPM scanning is broken #4559

Related PRs

• fix: change the type of the devDependencies field go-dep-parser#222

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).