added cache clean script

package.json

@@ -8,7 +8,8 @@
     "build:next": "ng build --base-href /next/ --aot --delete-output-path",
     "build:prod": "ng build --configuration production --output-path dist/rc --aot --delete-output-path",
     "watch": "ng build --watch --configuration development",
-    "test": "ng test"
+    "test": "ng test",
+    "clean": "ng cache clean && npm cache clean --force"
   },
   "private": true,
   "dependencies": {