pub fn req_for_kind(&self, kind: DependencyKind) -> DependencyReq<'g> {
        match kind {
            DependencyKind::Normal => self.normal(),
            DependencyKind::Development => self.dev(),
            DependencyKind::Build => self.build(),
        }
    }
Returns details about this dependency from the section specified by the given dependency
kind.
guppy/src/graph/graph_impl.rs