[bugfix]: specify depth in npm ls to avoid errors from uninstalled peerDeps

[kindoflew]

In npm v8, the ls command will default to --depth=0, but to be safe, we'll include it for now.

Context:
While attempting to run the CLI in a project that had some dependencies with missing peerDeps, it crashed because of npm errors relating to them. Using depth=0 explicitly will avoid this because dependencies (prod, dev, and peer) that are specified in package.json will always be included after npm install.