pub fn query_workspace(&self) -> PackageQuery {
        self.query_forward(self.workspace().member_ids())
            .expect("workspace packages should all be known")
    }
Creates a new forward query over the entire workspace.

`query_workspace` will select all workspace packages and their transitive dependencies. To
create a `PackageSet` with just workspace packages, use `resolve_workspace`.
guppy/src/graph/query.rs