fix: determine correct LockfileType for yarn v2

[mhassan1]

• Ready for review
• Follows CONTRIBUTING rules
• Reviewed by Snyk internal team

What does this PR do?

Adds support for Yarn v2 with the --yarn-workspaces flag

Where should the reviewer start?

package.json

How should this be manually tested?

snyk test --yarn-workspaces in a Yarn v2 package that contains Yarn Workspaces

What are the relevant tickets?

https://github.com/snyk/snyk/issues/1322

[orsagie]

Hey @mhassan1 thanks for your contribution! We actually already have detection for yarn v2 in our parser, but you pointed out that we were not doing it in both buildDepTree methods. I added this detection in the parser, so that we don't need this extra check in the Snyk CLI : snyk/nodejs-lockfile-parser#84.
Once the above is merged in, let's change this PR to update the dependency of snyk-nodejs-lockfile-parser, and keep the test you added :)

[orsagie]

Big 👍

[orsagie]

closing and reopening to trigger test

[orsagie]

@mhassan1 I need to create a separate branch to trigger the tests. Can you send me your email so I can add you as contributor? to or@snyk.io

[lili2311]

@orsagie I raised a PR and cherry-picked the commit :) Closing this one