fix: Support pnpm patches in prune

[chris-olszewski]

Addresses #1963

This PR fixes two issues with the current implementation of prune for pnpm:

• Pruning the importers section of pnpm-lock.yaml, previously the pruned lockfile would pickup any direct dependency changes for any project in the workspace
• Copy dependency patches into the output directory while pruning

Fixing the first issue required updating the Lockfile interface take a list of workspace dependencies when constructing the subgraph. This is required as workspace dependencies don't appear in packages in the pnpm lockfile format. Taking a quick look at the npm lockfile format, this additional information will be helpful when implementing npm prune so it seems sensible to make this addition.

The current implementation of copying dependency patches copies all patches instead of those that are strictly necessary. This was done due to the fact that pnpm duplicates patch info in package.json and in order to only copy the necessary patches we would first need to learn how to prune package.json. This should be done in the future, but is outside of the scope of this fix.

[vercel]

@chris-olszewski is attempting to deploy a commit to the Vercel Team on Vercel.

A member of the Team first needs to authorize it.

[chris-olszewski]

pnpm encodes workspace paths using / as a separator regardless of the separator the OS uses

[gsoltis]

I don't think importers needs to be passed via pointer, maps are already references under the hood.

See https://go.dev/blog/maps

Map types are reference types, like pointers or slices

[chris-olszewski]

Ah, good catch.

[nathanhammond]

This is an approval contingent on the patch location within workspaces. If that comes up as "not root every time" then I'd like another look.

[nathanhammond]

Suggested change

[nathanhammond]

(change requested: constrain path type)

I only quickly checked, but PatchedDependencies is probably an AnchoredUnixPath from the lockfile? This will help us guarantee correctness downstream.

Suggested change

	func (p *PnpmLockfile) Patches() []string {
	func (p *PnpmLockfile) Patches() []turbopath.AnchoredUnixPath {