Restore the state of the skipUpdate flag to the sate before running the recursive build and also add some comments

Signed-off-by: Cosmin Cojocar <cosmin.cojocar@gmx.ch>

pkg/downloader/manager.go

@@ -126,7 +126,11 @@ func (m *Manager) BuildRecursively() error {
 		return err
 	}
 
+	// The local repositories are already updated by the root build. Skip the update
+	// for each dependent chart to improve performance.
+	prevSkipUpdate := m.SkipUpdate
 	m.SkipUpdate = true
+
 	baseChartPath := filepath.Join(m.ChartPath, "charts")
 
 	// Do a Breadth-first traversal over the chart dependencies and
@@ -161,6 +165,9 @@ func (m *Manager) BuildRecursively() error {
 		}
 	}
 
+	// Restore to the original value before running the recursive build
+	m.SkipUpdate = prevSkipUpdate
+
 	return nil
 }