Run npm-install and add npm install as a post update option (#42)

Reviewed-on: #42

renovate.json

@@ -4,5 +4,15 @@
     "local>server/Renovate-Template:renovate.json",
     "config:recommended",
     ":automergeLinters"
+  ],
+  "packageRules": [
+    {
+      "matchManagers": [
+        "npm"
+      ],
+      "postUpdateOptions": [
+        "npmInstall"
+      ]
+    }
   ]
 }