refactor: refactor deps updater

Author: zdm

lib/package.js

@@ -730,7 +730,8 @@ export default class Package {
             else {
                 dependency.updatable = dependency.current !== dependency.wanted;
 
-                if ( dependency.updatable ) {
+                // some peer deps can be optional, so we additionally check dependency.current
+                if ( dependency.updatable && dependency.current ) {
                     include = true;
                 }
             }