Update the package.json name to match the actual npm published packag…

…e. (#3570)

package.json

@@ -1,5 +1,5 @@
 {
-  "name": "Polymer",
+  "name": "@polymer/polymer",
   "version": "1.4.0",
   "description": "The Polymer library makes it easy to create your own web components. Give your element some markup and properties, and then use it on a site. Polymer provides features like dynamic templates and data binding to reduce the amount of boilerplate you need to write",
   "main": "polymer.html",