Add support for the latest version of yarn

Looking in the logs for our Codesee action, I saw

```
  Unable to parse yarn.lock: /home/runner/work/ORG/REPO/yarn.lock
```

We're using yarn 4, so I'm guessing there's no support for this currently.

Are there any plans to support the latest version of the yarn lock file? Specifically:

```
__metadata:
  version: 6
  cacheKey: 8
```