[FEATURE] Support pnpm-lock.yaml

[JU12000]

• What are you trying to do?

I'd like to scan workspaces which are managed by the PNPM package manager. I'm able to do this with the Nexus IQ CLI.

• What feature or behavior is this required for?

My monorepo uses PNPM, generating npm-lock.json files is not an option because of the pnpm 'workspace:*' url I'm using in many of my package.json files.

• How could we solve this issue? (Not knowing is okay!)

Nexus already supports pnpm, should be as easy as copying/utilizing their implementation.

• Anything else?

Thank you for creating and maintaining the plugin, it's massively helpful 👍

cc @bhamail / @DarthHater